He will be in the rotation in the future, but with 5 established starters going into the season, they decided to use him in the BP until he had a spot. This was due to his BP performance at the end of last year. Couple that with Foulke's lack of innings in ST and need for a little work, and voila, Papelbon closes games to begin the year. I don't think this is a long-term role for him though (provided Foulke continues to get better and better, which he has thus far).