Many people, including myself, wrote off J.P. Howell as someone who could be a contributing member to the ballclub this season. Coming into this season, Howell had a career WHIP over 1.60 and has never shown himself to be capable of pitching on the major league level. However, up to this point in the season Howell is sporting a WHIP under 1.15 and has vultured four wins like your fat uncle on the last piece of pecan pie at Thanksgiving. Has the switch to the bullpen caused this change, has he done something differently, or has he simply just been lucky?
If you ask any pitcher, they will tell you there is a different mental approach involved in coming out of the bullpen. Previously in his career, J.P. has been a starter who has been prone to give up the big hit at important situations. His OPS against for his career is .843 in high leverage situations, .792 in medium leverage situations, and .760 in low leverage situations. This shows he has not shown the ability to pitch well in high pressure situations throughout his career, but most of his career has been as a starter. Throughout this entire season out of the bullpen, we have seen a different J.P. who performs his best in high pressure situations. His OPS against for 2008 is .361 in high leverage situations, .422 in medium leverage situations, and .772 in low leverage situations. This guy is a stopper out of the bullpen. He has come in and gotten the big outs when the team has needed him most. Those that feel that the mental change from starter to bullpen has made him a better pitcher could make a valid argument based on these numbers.
Besides the obvious change from starter to the bullpen, what else has J.P. been doing differently to make himself better? When watching him pitch this season, it has been obvious that his best pitch was has been big breaking curveball. He has been deadly, when he has been able to spot that accurately. What will amaze you is that he has just recently begun throwing it on a consistent basis at the major league level. If you go back to 2005 when he was with the Royals, he threw his curveball only 1.3% of the time while lobbing up his fastball 61.3% of the time. However, this year he has thrown his curveball 20.7% of the time while only throwing his fastball 54.0% of the time. He went from not having his curveball as a viable pitch to having it be his go to strikeout pitch. This has also had an added effect on his fastball. Not only does throwing more offspeed make his fastball seem faster, but coming out of the pen has added more life to his fastball. The last two seasons his fastball averaged 82.7 mph while this season it has jumped up to 85.8 mph. He has also thrown his changeup much less, as it was never too effective before. His changeup was previously thrown 23.2% and has now dropped down to 9.2%. Instead of using an offspeed pitch with no movement, he now uses his curveball to mix with his fastball and has been quite deceptive for hitters.
For a pitcher to make such a great turnaround in just one season, any person who looks at stats must check to see how lucky they have been. The statistics show that Howell has been a bit lucky so far as his xBABIP has been .299 while his BABIP has been .254. Last season, his xBABIP was .348 with .391 as his BABIP. This shows he was unlucky during his stint last season. Although his luck has changed this season, it does not come close to covering the massive Ty Pennington-esque makeover. The fact that his xBABIP has dropped nearly .50 shows that he has been pitching much better with luck not being a factor. His small amount of good luck so far might lead to a slight regression in the future, but nothing major.
When wondering what is the reason that he has been so improved this year, I believe you have to account for all of the possible suggestions. The mental change from starter to the bullpen has suited him well. He has made changes in his approach and pitch selection. He also also been a bit lucky. When you add all of these things up, it explains how he has been able to transform into a great asset to the team. We can expect so see good production from Howell throughout the rest of the season in this capacity.