CC Sabathia - The signing of AJ Burnett has made everyone forget about the number of Sabathia pitches Sabathia threw at the end of last year (especially on short rest), and the fact that the guy has thrown 494 regular season, and 19 postseason innings in the past two years. He's been nothing if not durable, throwing at least 192 innings in every season of his career except his first, in which he threw 180, but one has to wonder how long that will hold up.
Chein Ming Wang - Wang had a freak injury running the bases last year missing about half the season, and has dealt with some fingernail issues in the past. He's a pretty good bet to take the mound every 5 days, but the apparent disrespect he has been shown by the Yanks makes you wonder if they know something we don't.
AJ Burnett - Burnett has quite the intimate relationship with the disabled list, making several visits for both elbow and shoulder issues. He also has the reputation of not wanting to take the ball unless he was 100%. At the press conference announcing he and Sabathia's signings he claimed that Roy Halliday taught him to be more professional and understand his body better. But the injury history speaks for itself.
Joba Chamberlain - We have the least data on Joba, but the reason he fell to the 41st pick was his injury history. He didn't have any trouble when he was used out of the bullpen in accordance with The Joba Rules, but when I think of him as a starting pitcher, I can't get the image of him grabbing his shoulder in Texas out of my mind.
Phil Hughes - Aside from his stellar minor league numbers and short spurts of adequacy at the major league level, he hasn't given any indications that he can stay healthy or effecitve enough to pitch a full major league season. If he wins a spot in the rotation, you will likely see more of Ian Kennedy or Alfredo Aceves than you want to.