BOSTON -- The Red Sox optioned starting pitcher Justin Masterson to Triple-A Pawtucket on Monday, with plans to convert him into a relief pitcher.
Manager Terry Francona said the team is preparing to recall right-hander Clay Buchholz, who will take Masterson's spot as the fifth starter. Buchholz was sent to the minors to work on his fastball command after spending the last two weeks of May on the disabled list.
"We think getting Justin getting acclimated to the bullpen has a chance to really help our ball club," Francona said. "There's a couple of ways to do it. You could just give him the ball and send him out there. I don't think that's the best way to develop somebody to pitch meaningful innings. So we sat him down and talked about it."
Buchholz, who threw a no-hitter in his second major league start on Sept. 1, against Baltimore, struggled in his first eight starts this season for Boston. He was 2-3 with a 5.53 ERA before tearing the nail on his right middle finger.
For now, the Red Sox recalled first baseman Jeff Bailey from Pawtucket to take Masterson's place on the roster.
"We wanted to, at some point, get Clay back here and get him in the rotation and I think we've been alluding to and talking about that," Francona said. "We'll go from there.
"There's not a firm timetable but the idea is to get him acclimated to where he can help us. In the meantime, Jeff Bailey will be here until we can activate Clay."
The team later said Buchholz is expected to start Friday against Baltimore.
The right-handed Masterson has been impressive as a rookie starter, going 4-3 with a 3.67 ERA in nine starts. He lost his last two starts, including Saturday, when he allowed two runs in six innings at Yankee Stadium.
With a sinking fastball and slider, Masterson is considered a weapon against right-handed batters, who are batting just .170 against him.
The Red Sox have been looking for consistency from their middle relief corps as a bridge to closer Jonathan Papelbon. Relievers Mike Timlin, Craig Hansen, Hideki Okajima and Manny Delcarmen have all struggled at times in the seventh and eighth innings.