Andy Pettitte's performance in 2012 was short and sweet. For a 39 year old pitcher turning 40, short was expected, but the 2.87 ERA and 3.48 FIP were a shocker after a year on the retirement shelf. The lefty has continued his success in his 3 starts so far, giving the Yankees 22.1 innings, allowing just 5 earned runs. Since returning from retirement, Pettitte has now pitched 97.2 innings and he's looked less like a number three pitcher in the rotation, and more like a 1b. His 2.67 ERA over the last 2 years has been stunning, and the Yankees have to be thrilled with the results.
With the injury weaknesses and back of the rotation struggles this April, Pettitte has stood out and carried the team with dominate performances over three games. His importance in the early part of 2013 continues to be key for the team, but there are some signs that the south paw's results could be due for some regression.
No one expects Pettitte to continue pitching to a 2.01 ERA, but he's shown some odd tendencies thus far. His K% has dropped to just 14.1%. The most glaring pitch has been the changeup, which he uses to neutralize right-handed batters. In 2012, the changeup drew a 13.3% whiff rate, and he thus held right-handers to a .242/.308/.372 tripleslash. In 2013, the whiff rate has fallen to just 6.7%, and right-handers are batting .290/.323/.452.
While there is small sample size occurring in the early numbers this year, the 75.1 regular season innings that Pettitte pitched in 2012 were also limited enough to question. At this point, the left-hander is drawing much fewer strikeouts in the early going, and is only holding onto his low ERA by allowing a ridiculously and unsustainable low 10.4% line drive rate. This after allowing another well-below career average 14.9% line drive rate in 2012. His left on base rate has likewise sky rocketed, and in 2013 it's way up to 89.6%.
This doesn't mean that Pettitte is doomed, especially not with just 3 starts to his name, but with his start tonight, I will now stay mindful of the low strike out rates and signs of struggle against opposite handed hitters. With back spasms already complicating his season, relying on Pettitte is asking for trouble, both in terms of his health and probable regression. This isn't to say that he'll collapse, but relying on him for 7+ quality innings every start is hard to imagine, and the Yankees will soon need for the back of the rotation to pick up some of the slack. Phil Hughes' last two starts were promising, but Ivan Nova (or his replacement) will need to carry some of the load with the 40 year old Pettitte adjusting to his aging body.