Masterson (shoulder) threw a bullpen session last Friday and will throw at least three sessions before being sent out on a rehab assignment, the Boston Globe reports. Since Masterson was placed on the disabled list, the Red Sox starting staff have performed well, including his replacement, Steven Wright. There's been no mention of moving him to the bullpen, but it's something to keep in mind as Boston's starting rotation has righted itself after April's debacle.

Masterson (shoulder) worked on his mechanics and did some throwing from flat ground again Saturday, Pete Abraham of The Boston Globe reports. Masterson did the same prior to Friday's game, and continues to rehab from shoulder tendinitis that sent him to the disabled list. His timetable to rejoin the club remains a bit unclear, but a return when available still seems possible at this point. However, he'll need to continue progressing without setbacks for that to happen.

Masterson (shoulder) did some light throwing in the outfield prior to Friday night's game, the Boston Globe reports. Masterson, who was placed on the disabled list with shoulder tendinitis Thursday, was working on his mechanics with Boston's new pitching coach Carl Willis.

Masterson was placed on the 15-day disabled list Thursday, Alex Speier of the Boston Globe reports. Masterson was expected to move to the disabled list, and that has now been a confirmed move. The Red Sox recalled Robbie Ross Jr. on Thursday in a corresponding move, and he'll likely take over Masterson's place in the rotation while he's on the shelf.

Masterson will likely be placed on the disabled list, Scott Lauber of the Boston Herald reports. Masterson's arm is reportedly suffering from fatigue, though no there's no specific injury related to it. Steven Wright or Robbie Ross Jr., would be the likely candidates to take over his spot in the rotation.

Red Sox manager John Farrell would not commit to Masterson making his next start after the right-hander was shelled for six runs on six hits (two homers) and a walk in 2.1 innings in Tuesday night's loss to the Athletics, the Providence Journal reports. "Clearly, he's not right," Farrell said. Masterson said he feels fine "other than not making good pitches," but Farrell intends to put the pitcher through some medical testing between now and his next scheduled start. Tuesday's shellacking comes six days after Masterson permitted six walks and seven hits in 4.1 innings against the Rays. Steven Wright came on in relief of Masterson, throwing 5.2 innings. He is a candidate to replace Masterson in the rotation.

Masterson (2-1) was awful Wednesday, putting 14 men on base -- seven hits, six walks and a hit batsman -- and allowing four runs over 4.1 innings. He struck out just one batter and threw a wild pitch. With all those baserunners, Masterson was lucky to get away with only four runs on his record. He's been highly inconsistent in the early going, compiling a 23:18 K:BB and 5.18 ERA over 33 innings, leading to the unavoidable conclusion that Masterson simply isn't a very good pitcher anymore. His formerly mid-90s fastball has descended well into the 80s, and there are precious few (if any) optimistic peripherals to point at.

Masterson surrendered two earned runs on six hits, walking three and striking out two over six innings on Friday. Masterson pitched well on Friday as his offense struggled to provide him run support. He earned the no decision and brought his ERA down to 4.71.

Masterson struck out six and walked three while holding the Orioles to one run on three hits over five innings en route to his second win of the season Monday. Although he struggled to get ahead of hitters in Monday's start (eight first-pitch strikes to 21 batters faced), Masterson avoided damage getting outs on the ground and missing bats while working around the trio of walks. As part of a two-start week, Masterson will face the Orioles again Saturday at Camden Yards.

Masterson gave up seven earned runs on eight hits and three walks with four strikeouts in 4.2 innings Tuesday against the Nationals. This was pretty disappointing following Masterson's strong first start of the season against the Phillies last week. Of course, that may be the problem. In his first outing he was facing one of the worst lineups in baseball and Tuesday he faced the team that was favored in the preseason to represent the National League in the World Series. Boston has too many young internal options to allow Masterson to languish in the rotation if Tuesday's outing becomes a trend. He will have a chance to bounce back Monday against the Orioles, but it might be best to take a wait-and-see approach in most formats.