In the second half last year, Brad Bergesen changed his approach on the mound and that helped turn his season around some. He's carried that forward into 2011, and the results - ERA aside - having been similarly encouraging (4.39 FIP with an xFIP to match). Interestingly, though his xFIP is almost exactly the same now as it was in his rookie season, Bergesen is getting those results in very different ways. He now looks like a flyball pitcher, instead of the sinkerballer of years past.
Bergy has started to eschew his formally signature pitch a little* more, instead utilizing the four-seam fastball - and that's caused his groundball rate to tumble from 50% to just 37%. He's made up for it though, by striking out more batters (K/9 up to 5.9, which is still below average but a full point higher than it had been) and improving his control (if only slightly - 2.2 BB/9). For the first half of 2010, part of Bergy's problem was that he was having a little trouble spotting his sinker (and his walk rate went up). I don't know what happened to cause that (injury?), but it looks to me like he's made the adjustment to go with the offering he can more consistently throw strikes with. Going by FanGraphs' Zone%, almost 56% of Bergesen's pitches this year have been in the strike-zone, compared to less than 47% last year (league average both seasons is ~46-47%).
* Some of the extra fastballs are coming from sinkers, but some of them are also coming from off-speed pitcher (change-ups and curveballs - the latter of which he doesn't throw anymore at all, it seems).
Other than the emphasis on the different type of fastball, the four-seamer itself is faster by about 1 mph and overlaps with his two-seamer less (it's got less sink to it) - consistent with the changes from later last season. Additionally, he's missing more bats with the pitch, generating a whiff rate close to 13% (compared to the 6-7% he got before).
If Bergesen keeps missing pitches with his fastball, he might actually have some room to improve his strike-out rate further given that his slider has been coming in harder and without quite as much bite as before - and he's leaving it up and in the middle of the plate more, instead of getting it down and away from righties. That's probably what's contributed to the lower whiff rate on the offering this year, and if he corrects that I wouldn't be surprised if his strike-out rate over 6 K/9 range*.
* I won't be surprised if it falls below 5 K/9 either - closer to his career numbers - but I can at least see a plausible path for progress as well.
The usage patterns have also been interesting from a platoon perspective - whereas before he'd throw more four-seamers relative to two-seamers to right-handed batters vs. left-handed batters (that is, with a lefty up he'd lean on the sinker more than usual), now his fastball distribution is pretty much the same no matter who's at the plate. The only difference is that righties get the slider as almost the sole off-speed pitch, while lefties see the change-up mixed in as well. I don't expect this is the only reason, but perhaps this has had some effect on the narrowing of Bergesen's (xFIP) platoon splits this year:
|vs. RHH||vs. LHH|
This makes some sense, since the sinker is the pitch with one of the largest platoon splits (if not the largest), so using it less versus lefties (against whom it's relatively worse) should be a good thing. And he's still using the pitch almost as much against righties, so there's not that much loss there (besides the quality/control of the offering perhaps being worse).
A more general point in Bergy's favor is that he's actually faced way more lefties (77) than righties (43) so far in 2011, whereas in the past it's been close to a 50-50 split. So there's some upside there as well, since as he faces more right-handed batters, his numbers should improve.
It's still early in the season, and who knows if batters will adjust to the changes Bergesen has made (or even if Bergy will continue in this manner). But I still think he can be a decent back of the rotation starter, even if it's not going to be in quite the same form I originally expected. Maybe Jeremy Guthrie can even teach him his low BABIP trick, so the O's can have two low-BB, low-K righties who outperform their peripherals in the rotation.
Stats: FIP, xFIP, K/9 & BB/9, GB%, PitchFX