I figured this was worth it's own thread because of the significance of the player.
He's being skipped till next Monday because of shoulder fatigue. Apparently it contributed to his bad start last Friday. He threw a bullpen yesterday and felt fine, and he won't throw again till Friday. The Yankees' believe it's not serious.
I basically summarized from here:
http://yankees.lhblogs.com/
This reminds me of El Duque in 2004. He was supposed to really contribute in the playoffs after being surprisingly good in the regular season, and he came down with shoulder fatigue about a week before the playoffs. He only ended up starting once in that postseason, and was pretty shaky, not even finishing five innings.
Obviously, they need Pettitte to be healthy to have their best shot at winning in the playoffs this year. If he's out, they would have to slot Chamberlain into the ALDS rotation. But even worse than that, if they make it out of the ALDS, they would need a fourth starter for the ALCS. I would imagine that they wouldn't trust someone like Sergio Mitre or Chad Gaudin, and they would give it to Alfredo Aceves. Either way, it would present a huge problem.
I'm getting ahead of myself, but having a healthy Pettitte is key.