SEATTLE -- While putting Justin Masterson through a medical exam on Wednesday, the Red Sox found some inflammation in his right shoulder. A day later, the struggling righty was officially placed on the 15-day disabled list.
Knuckleballer Steven Wright will take his place in the rotation, starting with Sunday's contest in Seattle.
"And clearly, I think we've seen over the last two starts, it's had a negative effect on the overall stuff and the action to his pitches," said Red Sox manager John Farrell. "I felt like it was a time to back him out of the rotation, get over this, and insert Steven, who went five-plus innings the other night. Obviously he's stretched out to no pitch restrictions in terms of the number thrown. He's ready to go on Sunday here."
Wright, who made one spot start for the Red Sox in each of the last two seasons, is eager for his latest opportunity.
"My job is to throw quality pitches," said Wright. "It's their job to make the decision if I'm going to start or relieve or go to Pawtucket. That's out of my control. For me, I'm just going to do whatever I can to help this team win on Sunday, and after that, it's whatever they want me to do."
To fill Masterson's spot on the roster, the Red Sox recalled left-hander Robbie Ross Jr. from Triple-A Pawtucket.
Masterson was unable to complete five innings in either of this last two starts, allowing a combined 10 earned runs over just 6 2/3 innings. Those outings came after the veteran began the year 2-0 with a 4.71 ERA in his first five starts.
Masterson was hoping to rediscover his ace form in 2015 after a disastrous '14 campaign in which he racked up a 5.88 ERA over 28 combined outings with the Indians and Cardinals, all while trying to pitch through lingering oblique woes. Masterson was seemingly healthy when he reported to camp with the Red Sox this spring, but he's continued to struggle with getting his velocity back to his typical mid-90s mph.
Ian Browne is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.