Matt Garza is good. Very good. His stuff, as many a catcher will attest, is as filthy as a chimney sweep. Yet, despite this, he has produced the results of a merely above-average starter. This year, in-the-know Cubs fans have observed The Tale of Two Garzas — the story of a devastating strikeout pitcher who just can’t seem to keep the scoreboard clean.

What gives? Which is the real Matt Garza? The one who can make Albert Pujols look like Neifi Perez, or the one who watches opponents slap pitches for key double after key double? Well, the truth lies somewhere in between.

Garza is never hard to find in a dugout. Leaning on the railing, nervously spitting sunflower seeds, waiting for any reason to vault over the railing and scream a little, the Cubs third starting pitcher is always totally immersed in the game, whether he’s pitching or still four days away from taking the mound. But the Cubs didn’t trade a hefty slice of their farm system for a cheerleader — they wanted Garza win some games. Unfortunately for the Cubs, that hasn’t happened very often this year.

When the Cubs acquired Garza this offseason, they were getting a starter who had pitched nearly 200 innings for three straight seasons with an ERA under 4.00. So far in 2011, Garza has been decent, but not lights-out-go-to-bed-you’re-grounded, sporting a 3.72 ERA.

After his trade to the North Side, the common fear surrounded his stadium change. Despite his good ERA with the Tampa Bay Rays, Garza allowed more than the league average in homers in both 2009 and 2010 — despite playing in a park known to depress power numbers. Moving to Wrigley Field, where a windy day can transform a popup into a double and a Mohawk into a comb-over, Garza looked poised for some serious struggles.

Instead, he changed his approach and found a new form of success.

In 2010, Garza threw his four-seam fastball (the straight or rising fastball) about 60 percent of the time, essentially challenging hitters to do their worst. This approach, coupled with the Rays’ superior defense, made Garza relatively successful. However, without Evan Longoria snaring grounders like a demigod, the righty needed a more defensive-independent approach. So he replaced his extra four-seamers with a slew of bendy and wobbly pitches: more two-seamers (22 percent), sliders (21 percent), changeups (12 percent) and curves (11 percent).

Garza has gone from a fastball-obsessed flamethrower to a crafty right-hander, who happens to sport a flammable fastball. The result has been a significant uptick in swinging strikes (7.5 percent in 2010 to 11.1 percent in 2011). Only his curveball seems to have lost some whiffs, but nearly every other pitch has induced many more frustrated batters; his changeup alone went from 33 percent whiffs to more than 54 percent.

His ERA (3.72) is nearly his career best; his strikeouts per nine innings (10.99) are way up from his career norm (7.36); and despite the extra K’s, his walks per nine (3.23) are near his career norm (3.18). Everything but the ERA screams, “Elite!”

In the National League, Garza gets to face pitchers and pinch hitters — essentially giving an extra one or two strikeouts every game over his former league — but still, no one anticipated that Garza would (1) change his approach and (2) become a strikeout machine because of it.

Fielding independent pitching (FIP), a statistic which combines strikeouts, walks, homers and hit-by-pitches to predict ERA, suggests Garza has actually been playing at a sub-2.00 ERA level. Through his first nine starts, Garza has mustered a 1.82 FIP, good for second in the majors behind Roy Halladay.

So is Garza on the road to Cy Young consideration? Well, no. Not really.

One of the reasons Garza’s FIP is so low is the same reason his ERA is so high: BABIP. Garza’s batting average on balls in play is extraordinarily high this year. Coming into his 10th start, Garza brings with him the highest BABIP of his career (.362). For pitchers, balls in play tend to go for only about a .300 average. When they fluctuate from that number, it oftentimes means the pitcher is rather lucky or unlucky.

Garza’s high BABIP, which is about 60 points higher than his career norm, has not only allowed extra runs to score (increasing his ERA), but has also helped depress his FIP. Like the dandelion, which chokes out the grass but offers its own little flower, Garza’s high and unlucky BABIP has led to more strikeouts. As noted before, Garza’s K’s are way up (about 55 percent up per inning). However, if we look at his strikeouts per batter faced, he has only gone from 19 percent (in 2008 through 2010) to 28 percent — up only 9 percent, not 55 percent.

On top of that, Garza has allowed only one home run this year, after allowing 28 in 2010 and 25 in 2009. Though his new pitch selection approach may certainly play a role, he still appears to have Lady Luck’s favor. Only 2.4 percent of Garza’s fly balls have gone deep this year, despite allowing around 10 percent the last two years. One must expect, especially given his home stadium, that he will return to his career norm.

So altogether, the Cubs have one tough pitcher to predict: He’s changed his approach significantly and seems to have increased his strikeouts; he’s pitched better than his record (2-4) implies and maybe even better than his ERA suggests; but he’s also pitched worse than his stellar K/9 and FIP report.

Which Garza will the Cubs get moving forward? Probably one similar to what we saw from 2008 through 2010, but over the next few years, Garza will likely continue to mature into one of the league’s better right-handers, improving to a 3.25-3.50 ERA pitcher over the coming years. For now, though, his new approach will likely only improve his play marginally, taking him from a 4.00 ERA pitcher to a 3.80 ERA pitcher.

In the meantime, he’ll at least be one hell of cheerleader.