If you've read the guest article that Aaron Brown wrote here a few days ago, you know how valuable closers will be in Rotohog. One side-effect of that is that closers with starter eligibility will be extremely valuable. Keep an eye on whether Joel Pineiro ends up as Boston's closer...even really bad closers will be worth more than any starter. If he doesn't win the role, watch whether Papelbon is moved back to the role. And watch closely to see if other teams end up with someone listed as a starter in the closer's role at any point this season.
EDIT: I just went through the entire list of players listed as starting pitchers, and found another one who may be a closer this season: Seth McClung is the frontrunner to be Tampa Bay's closer, although there are reports today that that is far from a sure thing.