Masterson (shoulder) will make another rehab start at Triple-A Pawtucket on Tuesday, Tim Britton of the Providence Journal reports. Masterson looked sharp in his third rehab outing with Pawtucket a few days earlier, giving up one run and striking out six over six innings. While he looks healthy and ready to go, the Red Sox don't currently have a starting role waiting for Masterson, with rookie Eduardo Rodriguez already excelling since arriving in the big leagues. Masterson may have to settle for a swingman role once he returns to the Red Sox, unless manager John Farrell ends up deciding that the right-hander rates as a better rotation option than the struggling Wade Miley or Joe Kelly.