Well I've been holding onto to this for a while, adding small things but considering Stacey's story on the Os pitching next year I decided to finish this up
Jeremy Guthrie had a horrible year in 2009. The only good thing that can be said is that he pitched 200 innings. However the two years before that he was an above-average pitcher at the MLB level. The obvious stipulation was that his FIP (fielding independent pitching or basically era with defense factored out) were over half a run higher than his ERA in both 2007 and 2008. Some sites were pointing at Guthrie regressing based just on the difference between FIP and ERA although that does not seem to have been the primary reason.
So what exactly happened and what can we expect looking forward?
One of the most interesting things about Guthrie is just how much he changed as a pitcher. Using the same stuff he changed from a balanced groundball-flyball pitcher (approximately 42-44% groundballs to 38% flyball) to an extreme flyball pitcher. His flyball rate became 46.5% compared to his ~38% norm while his groundball ratio decreased dramatically to 34.7%
There were theories abounding about whether his lack of a true spring training affected his pitching, similar to Verlander's 2008. For those who don't remember Guthrie was invited to pitch for the American WBC team. However, he was used infrequently and so never had the chance to get into shape for the season.
What's unusual is that with his new flyball tendencies his BABIP (batted balls in play) increased to close to .300 whereas flyball pitchers typically have low BABIPs. As a flyball pitcher he was unlucky with a high BABIP (for him). However his previous two seasons Guthrie had a decidedly below-average BABIP so regression was expected. The previous two years his BABIP was .277 and .267 respectively both dramatically below-average. This could just be his BABIP regressing towards the mean.
To me he reminds me of John Lannan of the Nationals. Both players outperformed their fielding-independent stats fairly dramatically due to a lower than expected BABIP. Nick Steiner wrote two articles trying to explore how Lannan had managed to pitch two years with such a low BABIP especially for a bad defensive team. In it he acknowledged that some pitchers have lower than expected BABIPs like Johan Santana. Nick Steiner tried to figure out how Lannan was lowering his BABIP for two years in parts 1 and 2 but couldn't find a relationship. I suspect that Guthrie may have a similar pitching ability when he is pitching like he was from 2007-2008 and not being the extreme flyball pitcher he was in 2009.
Probably the biggest problem for Guthrie this year was his homers. While Guthrie became a flyball pitcher, his homeruns per a flyball stayed static even though he was inducing many more flyballs. This should have decreased somewhat as a flyball pitcher. So I decided to check out hittrackeronline.com to get a closer look. Eight of his thirty-five homeruns allowed were labeled just enough. These are somewhat lucky homeruns which means that Guthrie probably suffered from some bad luck with his homeruns. We could reasonable expect Guthrie's homeruns to decrease next year. For more information on Guthrie's homeruns allowed click here.
One of the questions that needs to be asked is whether Guthrie will stay a flyball pitcher or revert back to the pitcher he was before. As a flyball pitcher in Camden Yards and in the AL East Guthrie gave up more than his fair share of homeruns. The one benefit he has as a flyball pitcher is that he has a strong outfield defense behind him (minus Reimold although he should improve when not playing on an Achilles injury all season long) The past three years the Orioles have beenslightly below-average with two below average seasons and their only positive average being from 2008 according to fangraphs UZR. Defense does not seem to be a true reason for Guthrie's low BABIP
If Guthrie reverts to being his normal self I suspect that his era will be higher than 2007-2008 probably right around 4.00. He should be a net positive as a mid-rotation starter. If he remains an extreme flyball pitcher it could be nasty with him posting a similar year although possibly mitigated somewhat by our outfield defense. I personally believe he will revert to being the pitcher of yore although he may give up slightly more flyballs than he used to.