Justin Masterson, RP
Mazz's grade: B+
As a starter, he gets a solid B; as a reliever, he gets an impressive A-. The one area of concern with Masterson remains his ability to throw strikes against lefthanded batters who have a .365 on-base percentage against him despite a .238 batting average. Still, the Red Sox bullpen began coming together when he joined the unit. Not a coincidence.
(Globe Staff Photo / John Bohn)