Masterson (shoulder) allowed two runs on four hits and three walks while striking out four in a rehab start for Triple-A Pawtucket on Tuesday. The start was Masterson's fourth while out on rehab. Masterson elevated his pitch count to 89 and is seemingly ready to return to Boston, though whether that is as a starter or reliever is not yet clear. We suspect he'll pitch in a relief role, but there's still some time on the rehab clock, so the Red Sox don't have to make a decision at this time.