Justin 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.

Masterson (shoulder) threw a bullpen session Friday and will throw at least three sessions before being sent out on a rehab assignment, the Boston Globe reports.

Analysis:

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.