A Buchholz Breakout?

Glance at Clay Buchholz’s ERAs over the 2008-2010 seasons, and you’ll be inclined to believe that the former phenom’s major league performance has progressed from ghastly (6.75) to good (4.21) to great (2.52). That’s a compelling narrative — the hot-shot prospect tosses a no-no during a September ’07 call-up, gets his head handed to him the following year and then makes the necessary adjustments to blossom into a full-fledged ace.

It’s a nice story. But it’s also misleading. In truth, Buchholz neither fell to the depths of despair that his ’08 ERA suggests, nor has he risen from the ashes like a phoenix this season for a Boston rotation suffering greatly from injury and underachievement. Throughout his big league tenure, Buchholz has been pretty good, but hardly elite.

In 2010, Buchholz has 5.72 K/9, 3.78 BB/9, a 51.5 percent ground ball rate and a 4.33 xFIP in 78.2 frames. For comparison, his xFIP was 4.28 in ’08 and 4.09 last season. The big change in Clay’s ERA is due to factors largely out of his control — his BABIP is .268 (.302 career average) and his home run per fly ball rate is just 4.2%. His career rate is 11%, right at the big league average.

The 25-year-old’s K rate is down from the previous two seasons (8.53 K/9 in ’08, 6.65 in ’09). His swinging strike rate is basically the same all the years, ranging from 9.7% to 9.9% (8-9% MLB average), but the culprit for the lack of punch outs appears to be the rate of contact made against Buccholz’s pitches thrown outside of the strike zone. He’s throwing more off-the-plate pitches in 2010, and batters are swinging at plenty of them. But they’re also connecting more often against those offerings:

Buchholz has thrown just 43.8 percent of his pitches within the zone this year (47.3% MLB average). Batters have gone after his out-of zone pitches 31.5% (28.1% MLB average). However, they have put the bat on the ball 67.6% (66.4% MLB average).

That’s a sizeable increase from the previous two seasons — in 2008 and 2009, hitters made contact with Buchholz’s out-of-zone pitches at a rate that was about seven percent below the major league average. This season, they’re making contact on those pitches at a clip that’s two percent above the MLB norm.

Pitch selection has played a role in the K decline. Buchholz has a four-pitch mix: a 93-94 MPH fastball, a hard-upper 80’s slider, a mid-to-high-seventies curveball and a 79-80 MPH changeup. According to Pitch F/X data from Trip Somers’ site, Buchholz has increasingly gone to his slider this season, at the expense of some changeups and curves:

His fastball has never garnered many whiffs, and neither has his curve. Buchholz’s changeup has always gotten a healthy number of swing-throughs. His slider produced plenty of whiffs in ’08, but it’s not missing many bats this year:

So more sliders, and fewer whiffs on the slider. In our splits section on the player pages, we have pitch usage by count. Buchholz is going to his fastball and slider (two pitches with below-average whiff rates) more often in two-strike situations, in place of his curveball and whiff-generating changeup:

(note: the numbers are rounded, so not all columns add up to exactly 100).

These changes in Buchholz’s approach help explain why he hasn’t missed as many bats as expected. His minor league K rates suffered over this period as well. Buchholz spent much of 2007 pitching between Double-A Portland and Triple-A Pawtucket, and he logged a good number of innings with the PawSox in ’08 and ’09. Buchholz’s major league equivalent K rates declined over the years — According to Minor League Splits, Buchholz’s work in the minors in 2007 translated to 9.8 K/9 in the big leagues, but that mark fell to 7.7 K/9 in 2008 and 6.7 K/9 in 2009.

Clay Buchholz has a fantastic minor league track record. He exhibits strong ground ball tendencies, and he was an elite strikeout pitcher during most of his days as a prospect. It wouldn’t be surprising if he took significant steps forward in the coming years. But the current version of Buchholz is more of a solid, low-four’s ERA-type than any sort of rotation messiah.