Masterson compiled a 2.36 ERA in 27 games and held hitters to a .231 batting average -- limiting right-handers to a toothless .196 batting average.

Not bad for a guy who was a starter while ascending through Boston's minor league system.

"It turned out that I did enjoy the bullpen stuff and the different roles even more than I thought I would," Masterson said. "You get mentally locked in every day rather than that one day of intensity as a starter.

"My control actually got a little better in the 'pen, too, and that made it a little easier to pitch."

Perhaps the biggest advantage to Masterson's excellent bullpen adventure is his Derek Lowe-like ability to throw sinker after sinker in the low 90-mph range with remarkable rubber-armed endurance.

That, along with Masterson's ability to neutralize right-handed hitters and get a clutch groundball when needed, gives the youngster an ability to fill one of several different roles in the Red Sox bullpen.

He can pitch long relief, middle innings, setup or even as a right-handed specialist assigned to get a clutch out or a double play.

"We're fortunate to have a pitcher of his abilities with that kind of versatility," pitching coach John Farrell said. "You could envision one scenario where he and (Manny) Delcarmen become multiple-inning relievers, and you could rotate them through and provide ample rest knowing that you've got (Ramon) Ramirez, (Takashi) Saito, (Jonathan) Papelbon and (Javier) Lopez as your matchups and closer."