Injuries will happen, especially to pitchers. Spots will open up due to attrition. I think you're right that the guys at AA and AAA have the most to worry about. How much time are they going to give Kintzler, Runzler or Loek Van Mil for example? Those guys are all 30+ years old and have little track record of success. Also, if spots open in the big leagues (Tonkin, Nolasco) they're going to be leaving the organization.