Go For the Ks, Strasburg

Stephen Strasburg had his workload managed for him last year, and he wasn’t particularly thrilled about it. This year, Strasburg is attempting to manage his own workload, adopting a pitch-to-contact approach to getting batters out in an attempt to keep his pitch counts down and help him stay fresh for September and October. The only problem is that it might not actually make things any better.

In the 251 innings Strasburg pitched from 2010 to 2012, opposing batters made contact just 74% of the time they swung the bat, the third lowest rate in the Majors for a starting pitcher. The lack of contact translated into a 31% strikeout rate, easily the highest K% of any starter, and it wasn’t even close. Clayton Kershaw, the pitcher with the next highest strikeout rate, checked in at 25.9%. The gap between Strasburg and Kershaw was as large as the gap between Kershaw and Anibal Sanchez.

Through his first three starts of 2013, Strasburg hasn’t looked anything like the Strasburg of old, at least in terms of contact. Opposing hitters are making contact on 80% of their swings, and his strikeout rate has fallen to just 19%, slightly below the league average. Meanwhile, his ground ball rate has spiked from 44.5% to 56.9%. Strasburg has essentially traded strikeouts for ground balls. Crash Davis would be proud.

However, despite the change, Strasburg hasn’t actually become that much more efficient. During the last three years, he averaged 3.92 pitches per batter faced while racking up a ton of strikeouts. As a pitch-to-contact groundball guy, he’s averaged 3.87 pitches per batter faced this season. Even if he stays on the mound for 220 innings this year, he’d face approximately 900 batters over the course of the season. At his current rate, that would take him 3,486 pitches. With his 2010-2012 numbers, 900 batters would take 3,526 pitches. That’s 40 fewer pitches over the entire year. One fewer pitch per start.

Even if we think that there’s some kind of learning curve, and that Strasburg will become more efficient as he gets more comfortable trying to get ground balls, the data shows that there just isn’t a big difference between the number of pitches thrown by groundball pitchers or strikeout pitchers.

The 25 starting pitchers with the highest ground ball rates in the majors last year — minimum 100 innings pitched — combined to average 3.69 pitches per batter faced. The 25 starting pitchers with the highest strikeout rates averaged 3.89 pitches per batter faced, so the groundball pitchers were more efficient on a per batter basis. However, because groundball pitchers have to rely on their defense to help them make outs, and there are more opportunities for batters to reach on a ground ball, the pitch-to-contact guys also faced more batters each inning. Here are the total comparisons for both groups.

Type	Pitchers Per Batter	Batters Per Inning	Pitchers Per Inning
Groundball Pitchers	3.69	4.25	15.68
Strikeout Pitchers	3.89	4.14	16.10

Over 220 innings pitched, the total difference in pitches per inning amounts to 92 fewer pitches thrown by the ground ball group. That’s basically three fewer pitches per game, which might be enough to earn Strasburg one extra batter over the course of each start. However, in exchange for that marginal gain in pitch efficiency, there’s a trade-off in performance.

The strikeout pitchers combined to post an ERA- of 87 last year, which means that as a group, they prevented runs at a rate 13 percent better than the league average. Meanwhile, the ground ball pitchers posted an ERA- of 102, so they gave up two percent more runs than league average while they were on the mound. Put simply, strikeout pitchers are more effective than ground ball pitchers, because strikeouts are outs and ground balls are only sometimes outs.

This doesn’t mean that ground balls are evil and that Strasburg should go for a strikeout of every batter, of course. There is a balance to be struck between complete domination and efficiency, and pitchers like Roy Halladay — at least, the healthy version we used to see — have shown that you can use both ground balls and strikeouts to great success. Strasburg doesn’t need to maintain a 30% strikeout rate to be a great pitcher.

But, he should aim higher than the 19% he’s struck out during his first three starts. If he keeps pitching to contact at this same rate, he’s going to give up more hits and more runs, and the cost to the team won’t be worth having him save a few extra pitches per start. Pitching to contact sounds like a good idea in practice, and there are times when it makes sense to just fire the ball down the middle and dare the opponent to do something with it, but more often than not, a pitcher’s best option is to just dispatch the opposing hitter himself. Leaving the defense out of the equation might be fascist, but it’s also more effective, and it doesn’t actually run up your pitch count in a meaningful way.