As we head into the final days of April, there is no question which team has looked like the best club in baseball so far – the Texas Rangers are 15-4 and have scored more than twice as many runs (107) as they’ve allowed (52). Both their offense (26.5 runs above average) and their bullpen (14.3 RAA) have been the best in baseball, while their starting pitching (28.5 RAA) has been the second best in the sport. They’ve been nothing short of dominant, and given how well they’ve played, you might very well have concluded that they’re the best team in baseball.

They very well may be, but history suggests that an outstanding win-loss record in April is often not a sign of things to come, and even the best starts to the season don’t suggest that a team is truly set for a strong finish.

In order to come up with a list of teams began the season as impressively as the Rangers, we looked at every instance since 1974 where a team posted a winning percentage of .700 or better in at least 15 games. In total, there were 45 such instances, so it’s fair to say that you’d expect at least one team per year to win 70 percent of their games during the first month of the season.

The best start any team has had over this span is the 1984 Detroit Tigers, who began the year 18-2, outscoring their opponents 120 to 63 in the process. They went on to win 60.6% of their remaining 142 games and then won seven of their playoff games in route to a World Series championship. So, certainly, a hot start can be indicative of a team that is on its way to greatness.

The second best start since 1974 throws a little rain on that parade, however. The 1987 Brewers were nearly as good as those ’84 Tigers, going 18-3 in their first 21 games to start the year. They would then proceed to win just 73 of their remaining 141 games and ended the year in third place in the National League East. After posting an .857 winning percentage in April, their May-September mark was just .518.

There are more stories like the ’87 Brewers than you might expect. If we look at the combined totals for all of the 48 teams that won at least 70 percent or their games in April, we get a combined first month record of 765-264, or an average winning percentage of .743. Those same teams combined for a 3,598-2,990 record over the remainder of the season, which works out to just a .549 winning percentage. Or, to put it another way, the average team in this sample went 16-6 in April and then just 77-63 the rest of the way.

In fact, eight of the 45 teams that won at least 70 percent of their April contests would go on to lose more games than they won the rest of the year. No team had a more significant crash than the 1978 Athletics, who went 16-5 in April and then 53-88 the rest of the year. They had the best record in baseball in the first month of the season, and then followed it up with the third worst record in baseball over the final five months of the year. They stand as the only team of the group to manage a 90 loss season in the same year that they dominated in April.

We know wins and losses can be highly variable based on things that may not continue over the course of a full season, so I also decided to look at how these teams performed in terms of runs scored and runs allowed. I broke the 45 teams into quartiles based on their ratio of runs scored to runs allowed.

First quartile: 1.81 RS/RA, .584 May-September Winning Percentage
Second quartile: 1.49 RS/RA, .516 May-September Winning Percentage
Third quartile: 1.37 RS/RA, .527 May-September Winning Percentage
Fourth quartile: 1.24 RS/RA, .573 May-September Winning Percentage

The top 11 teams by RS/RA did perform the best of the four groups, winning 58.4 percent of their May-September games, but note that the teams with the worst run differential actually performed nearly as well, and significantly better than both groups ahead of them by ratio of runs scored to runs allowed. In fact, the correlation between April RS/RA and rest-of-season winning percentage is even lower (.19) than the correlation between April win-loss record and rest-of-season winning percentage, and in reality, both correlations are pretty weak.

While a strong start is certainly preferable to stumbling out of the gates, history suggests that we simply shouldn’t draw too many conclusions based on how a team looks in the first month of the season. Even with how dominant the Rangers have been so far, other teams have looked just as good and fallen on their faces as soon as the calendar turned to May.

Derek Jeter is off to a scorching start this season, hitting .382/.411/.618 through his first 74 plate appearances. His .432 wOBA currently ranks among the league’s best, and is almost 40 points higher than the next best shortstop in baseball.

For Jeter, this is simply a continuation of his torrid second half to the 2011 season. Over his last 388 plate appearances, dating back to July 2011, Jeter has a .379 wOBA. The sample is small enough that we can’t conclude he is currently that great of a hitter, but it shouldn’t come as a surprise if he continues to rake this year.

His wOBA since the second half of last season is made even more impressive by his age, as Jeter produced those numbers after turning 37 years old. And even if he finishes in the .340-.345 range he’ll still find himself in limited company, historically, relative to his age and position.

At a time when most shortstops have moved onto easier positions or have been relegated to part-time duty, Jeter is not only still chugging along, but producing quite effectively. In addition to hitting well, Jeter has also settled into the -5 fielding runs range recently, which, while below average, is far from poor.

But perhaps what is most interesting about Jeter is his eventual place in history given his tremendous career and the opportunities the Yankees have afforded him. Most 38 year olds don’t continue to start 140+ games at the infield’s toughest position, but what started as a courtesy to a homegrown legend has become a justifiable decision given Jeter’s 2.5-3.5 WAR level productivity.

Only 22 shortstops have tallied 600 or more plate appearances after turning 37 years old, indicative of the inherent selection bias at work: by that age, most former shortstops are replaced by younger, more agile defenders, or better hitters capable of playing similar defense.

With a .343 wOBA since the start of the 2011 season, Jeter ranks third among those 22 shortstops, behind Hall of Famers Luke Appling (.375) and Honus Wagner (.368). After Jeter there is a steep drop in production to Barry Larkin (.317) and Ozzie Smith (.314). Everyone in the top five is either in the Hall of Fame, or in Jeter’s case, will be enshrined five years after his career ends.

When exactly will his career end?

If he sustains some semblance of his July 2011-April 2012 production over the remainder of the season, he will not only play shortstop in 2013, but he may be able to turn down his 2014 option and obtain another multi-year deal to remain in the infield.

While that’s far into the future, it’s impossible to discuss the hypothetical without also considering what those extra years will do to his career hits total. By virtue of that, his rank among the all-time greats would also improve, which speaks volumes for a guy who looked finished just two years ago.

ZiPS projects another 139 hits this season, which would give Jeter 165 for the season and 3,253 for his career.

That total would move him up from 18th to 13th on the all-time hits list. He would finish the season two hits behind Eddie Murray for 12th, 30 hits behind Willie Mays for 11th, 62 hits behind Eddie Collins for 10th, and 66 hits behind Paul Molitor for 9th.

Barring injuries, he will pass all of those players next year. If he puts together a fantastic 2013 season, then Honus Wagner is also in reach at 162 hits away. Jeter would also fall 165 hits behind Cap Anson for 7th and 166 hits behind Carl Yastrzemski for 6th. Assuming he plays through 2014, at the very least, meets his 2012 projection of 165 hits and then averages 145 hits over 2013-14, he would end that campaign with 3,543 hits. That total would push him ahead of Tris Speaker for fifth place. Not to get carried away, but even a mediocre 2015 season would push him ahead of Stan Musial for 4th.

Jeter has already won five World Series titles and achieved practically all the success a major leaguer can ever hope to achieve. But in his case, the valid question must be asked — given this rarified air, is it worth it to continue playing to rise up one of the more prestigious charts? Would Jeter be so prideful to retire a shortstop and finish 6th or 7th on the all-time hits list than to move to LF or DH for a few years to move up to fourth or even third all-time?

Then again, if he continues to produce the way he has lately, in the 2.5-3.5 WAR range, he might not have to move off of shortstop and would remain a productive member of the lineup instead of a novelty act. Two years ago, the Yankees entered negotiations with Jeter with the understanding that this would probably be his final deal as a shortstop with the team. While the 2012 sample is still small, his seeming resurgence and defiance against natural aging curves suggest he has something left in the tank and may yet get another lucrative deal to captain an infield.

Over the last five years, one trend has taken the National Football League by storm – shared responsibilities at running back. After years of wearing guys down as every-down backs and watching elite players suffer from short careers, NFL teams have decided to minimize the wear and tear and maximize their offensive weapons by acquiring two complementary players to share the workload and give the team greater flexibility in what they can do on the field. By taking advantage of individual strengths and weaknesses, as well as shuffling the players in and out to keep them constantly fresh, teams have found that they can get better performance and more longevity from their backs. The every down running back is becoming a thing of the past.

Perhaps its no coincidence, then, that the Milwaukee Brewers – who play just down the road from one of the most storied franchises in the NFL – have also jumped on the job sharing bandwagon for the most strenuous physical position on the baseball diamond. By having a pair of complementary catchers share the position, the Brewers are finding that they can get quality production at a fraction of the market rate.

In fact, through Wednesday’s games, the Brewers catching tandem had combined for a .343/.455/.771 batting line that was better than any other team has gotten from their backstops so far this year. While they obviously won’t keep hitting that well – those marks would fit right in to Babe Ruth’s career – they’ve shown that they can provide some strong offensive performance by playing the match-up game.

Lucroy, the right-handed half of the pair, has hit left-handers extremely well in his Major League career, posting a .294/.322/.512 mark against LHPs. In fact, nearly all of his power has come against southpaws, as he’s averaged one home run every 17.7 plate appearances against lefties, but has required 77.9 plate appearances versus right-handers for every home run hit agains them.

Kottaras, the left-handed bat, is exactly the opposite. He’s hit .242/.317/.466 against right-handed pitching, but managed just a meager .184/.308/.327 line against lefties. Like Lucroy, he maintains his ratio of walks to strikeouts fairly well against pitchers from both sides of the plate, but he drives the ball much better against opposite-handed pitchers.

Beyond just their differences in handedness, Kottaras and Lucroy also bring different approaches and skills to the table. Lucroy is the superior defender, which is why he gets more playing time even as the right-handed portion of the platoon, while Kottaras has a discerning eye at the plate that Lucroy doesn’t yet possess. This allows manager Ron Roenicke to determine who should play on a given day not just based on whether the opponent is throwing a right-handed or left-handed pitcher, but also play to the strengths and weaknesses of his own team and that of the night’s foe.

For instance, on April 11th, Roenicke chose to start Kottaras against Ryan Dempster and the Cubs. Dempster is right-handed pitcher, but he’s a right-handed pitcher who can struggle with his command and has a long history of high walk rates to left-handed hitters. Since 2002, Dempster has walked 12.5% of the left-handed hitters he’s faced compared to just 7.7% of the right-handed batters who have stepped in against him. Not surprisingly, Kottaras did well against Dempster, going 2 for 3 with a single and a home run, and then worked a ninth inning walk off Carlos Marmol – another RHP with serious command issues that Roenicke knew would likely pitch if the Cubs had a lead late in the game.

Major League teams have traditionally utilized their backup catcher in more of an alignment that stresses regularity, lining them up as the “personal catcher” for one of the members of the rotation in order to make sure that the starter gets a break every fifth day, and then working in the backup in day-game-after-night situations to further limit the starter’s workload. However, this kind of rigid pattern leaves teams open to the randomness of the schedule and doesn’t offer any opportunity to take advantage of match-up advantages that present themselves throughout the season.

Keeping your left-handed back-up catcher on the bench against a right-handed pitcher, only to start him the next day against a lefty simply because it’s his turn, is inefficient and gives the opposing team free outs that they don’t need. The personal catcher system also breaks down if the starter gets injured, as a tandem system gives both catchers the opportunity to work with each member of the rotation so there is no adjustment period if one of the two catchers has to become a regular for a period of time.

Using a tandem catching alignment could also help help stave off deterioration in late season performance. Last year, Major League catchers posted a .303 wOBA in September after posting a .309 mark during the first five months of the season. For other positions, offense is higher in September due to the warmer weather patterns, but the effects of a long year of crouching behind the plate can carry over to a catcher’s offensive performance down the stretch. It’s not a coincidence that the Rangers got a monster October from Mike Napoli, who was more of a 1B/DH in the early part of the season before moving to more regular catching duty in the second half of the year. By keeping his legs fresh, they got maximum offensive production during the playoffs, and were able to ride his bat straight to the World Series.

The benefits of a job share behind the plate are simply too great to ignore, and Major League teams will eventually follow in the footsteps of their NFL brethren. The only question now is how long it will take for other teams to begin copying what the Brewers are doing.

In almost every circumstance, April performance means little or nothing. Last year’s April stars included Placido Polanco, Brett Wallace, and Sam Fuld, each of whom would see their numbers come crashing back to reality as the season wore on. Over the course of 100 plate appearances, nearly any player can produce good or bad results.

However, there are some statistics that do have some predictive value, even in very limited quantities. Velocity, for instance, stabilizes extremely fast, as you’ll just never see Jamie Moyer fluke his way into throwing a 95 MPH fastball. On the offensive side of things, the closest equivalent to pitcher velocity is contact rate.

Adam Dunn swings and misses a lot, while Juan Pierre puts his bat on the ball nearly every time he swings. You don’t need to see many games before it becomes clear which guys make contact regularly and which guys do not. In fact, contact rate has the strongest year to year correlation of any offensive metric, and it is the most consistent skill possessed by any hitter. Sustained significant changes in contact rate are rare, and can generally be identified much faster than a change in some other skillset.

To show how quickly contact rate begins to matter, I looked at 125 batters who were full time players in both 2010 and 2011, and played nearly every day last April. As noted in the previous link, the correlation of contact rate between years is 0.9 (where 1.0 means that the two data sets would be exactly the same). However, by just adding in (at equal weight) the contact rate of these hitters in April of 2011 to their 2010 contact rate, the correlation with their 2011 contact rate rose to 0.96 – in other words, you could come very close to precisely predicting a player’s full season contact rate by just taking the average of his prior year contact rate and the mark he posted in the first year of a given season. Using this model at the beginning of May last year, you could have accurately projected the significant improvements by guys like Prince Fielder and David Ortiz while picking up on worrisome trends from Bobby Abreu and Shin-Soo Choo.

While we don’t yet have a full month’s worth of data for 2012, we are seeing a handful of players who are making more contact than they ever have before. While it is still too early to make any definitive declarations, these improvements in contact rate are more likely to be real than any other April performance, and could signal that these hitters have made legitimate steps forward at the plate.

Evan Longoria: 2011 Contact Rate – 79.6%, 2012 Contact Rate – 91.4%

After striking out in nearly a quarter of his plate appearances a rookie, his strikeout rate has been trending down every season since, and last year he only struck out once every six trips to the plate. Through his first six games, Longoria’s keeping up with the trend, as he’s only struck out twice in his first 26 plate appearances. In general, the only players who can sustain a contact rate over 90% are guys who slap the ball on the ground with regularity, but if Longoria can even push his contact rate in the 80-85% range, he could be in for a true breakout season. Very few players in the game can be both elite contact hitters and still drive the ball over the wall, but Longoria has the chance to put himself in that category.

Josh Willingham: 2011 Contact Rate – 75.4%, 2012 Contact Rate – 85.6%

From 2008 to 2010, Willingham was the epitome of consistency when it came to making contact, posting marks between 80.2% and 81.1% in all three seasons. Last year, his contact rate dropped to just over 75%, and the resulting spike in strikeouts at age 32 led to questions of whether he was headed for a steep drop-off in productivity. Instead, Willingham has come out of the gates thumping the baseball for the Twins, but he’s not just swinging for the fences either – he’s showing that he can still cover the plate at the same time. Given the Twins investment in him and their need for offense, his strong first week is as positive a performance as they could have hoped for.

Kyle Seager: 2011 Contact Rate – 84.5%, 2012 – 97.6%

As a diminutive infielder with moderate power who doesn’t draw very many walks, the only way for Seager to be a productive hitter is to put the ball in play as often as possible. During his rookie campaign in Seattle last year, he swung and missed about as often as an average hitter, and given his lack of other strengths, that looked like it could be a long term problem. However, he’s showing premier contact skills in the first week of 2012, and his performance is likely going to force the Mariners to keep playing him even after Mike Carp returns from the disabled list. Given the Mariners lack of offense in general, they can’t afford to bench any productive players, and Seager is giving some reason for hope that he can perform better at the plate than he did a year ago.

Every April, a few players get off to a bad start to the season. Last year, Derek Jeter (.250/.311/.272), Dan Uggla (.194/.250/.380), and Adam Jones (.218/.260/.414) all struggled out of the gates, but because of their strong track records, they were able to play the “it’s early” card, and their numbers improved significantly as the season wore on.

In general, you don’t want to evaluate a player based on the small sample of less than 100 plate appearances, and overreacting to an early slump is not a good idea. However, for these five players, if they don’t come out of the gates strong to begin the year, they might not get any more chances to turn it around.

Daniel Bard, SP, Boston

A mediocre spring training from Bard didn’t do much to calm the critics who think that his power repertoire plays up better in the bullpen, but the Red Sox opted to continue with his conversion into the regular season and give him a chance to stick as a starting pitcher. Their lack of reliable alternatives in the rotation likely helped Bard stick as a starter, but the thumb injury to Andrew Bailey – he’ll reportedly be out for 3-4 months – leaves them with similar issues in the bullpen, and the calls for Bard to move to the closer role will only grow louder if he doesn’t pitch well early in the season. With a clear need for another strong end-game reliever, the Red Sox won’t have the luxury of letting Bard get his feet wet as a starter. If he has a poor April, he’ll likely find himself back in the bullpen by May.

Chone Figgins, LF/3B, Seattle

Since signing a four year, $36 million contract to join the Mariners in 2010, Figgins has been nothing short of a disaster. Given a chance to bounce back last year, he hit .188/.241/.243 and was -1.2 WAR, meaning that the Mariners would have been a full win better had they just given his playing time to a random guy from Triple-A. However, the organization wants to get some value from Figgins’ contract, so they’ve shuffled their batting order in an attempt to give him one last chance with no excuses. Now back in the leadoff role, where he thrived in Anaheim, Figgins needs to show something offensively in a hurry. If he struggles again in April, the rebuilding Mariners won’t be able to justify keeping young players on the bench behind an unproductive 34-year-old. It’s fair to say that this is Figgins last chance at redemption, but he has to hit well early or that chance won’t last very long.

Jeff Niemann, SP, Tampa Bay

Hopes were high for Niemann when the Rays took him with the fourth overall pick in the 2004 draft, but between injuries and mediocre performances, he’s never lived up to his draft position. Now 29-years-old, Niemann had to battle Wade Davis for the final spot in the rotation, and while he was proclaimed the winner of the spring training face-off, the Rays won’t hesitate to go back to Davis if Niemann doesn’t pitch well. Few teams have a ready made replacement sitting in the bullpen looking over their fifth starter’s shoulder, but Davis’ presence is intensified by the four year contract he signed with the team last year. The Rays have a lot of incentive to get value from Davis, and a slow start from Niemann could easily push the team into flipping the two and sticking Niemann back in the bullpen.

Josh Collmenter, SP, Arizona

One of the better stories of 2011, Collmenter went from being a non-prospect who posted a 5.77 ERA in Triple-A the year before to a rotation stalwart for the Diamondbacks, and his success was a large part of the reason they ran away with the NL West. However, Collmenter’s success was probably not sustainable, as his 3.38 ERA was significantly lower than the 4.18 xFIP he posted, and the latter is more predictive of future performance than the former. Arizona fans are already clamoring to see top prospect Trevor Bauer in the big leagues, and the D’Backs may need to speed up his timetable if Collmenter gets off to a slow start. His spring training struggles have already sounded the alarms, so if Collmenter gets rocked a couple of times in April, expect Bauer in the big leagues by May.

Barry Zito, SP, San Francisco

Unlike the four situations above, the Giants don’t really have a great alternative to Zito, as presumed back-up starter Erik Surkamp is going to begin the year on the disabled list. The lack of options and the remaining $45 million still left on his disaster of a contract are allowing Zito to get one more chance to show he can still get hitters out, but the team is clearly tired of watching Zito take the hill. After another awful spring training where scouts reported that Zito was “throwing batting practice”, Zito is going to be on a very short leash, and if he struggles to begin the year, the team will find someone to take his place.