"His shoulder just wasn't responding the way we wanted it to," Lovullo said. "As a result, we felt like it would be best to look towards 2016."
During his time on the DL, Ramirez took a number of grounders as he attempted to transition from left field to first base.
"You'd prefer to see him play in a game, but we've watched him move around a bit," said Red Sox president of baseball operations Dave Dombrowski. "He's an infielder. He's going to have some growing pains but I think he's in a position where he's going to be able to play the position, from what I've seen.
"But I also think it will benefit him to go through six to seven weeks of Spring Training. I think you also have to have a secondary plan, but I think the reality is, he will be able to do it. He's committed to doing it."
Ramirez hit .249/.291/.426 with 19 homers in 105 games in his first season in Boston. He signed a four-year, $88 million deal during the offseason.
• Pablo Sandoval, who's been dealing with an upper respiratory infection the past week, has pneumonia. He'll be re-evaluated on Saturday, which will go a long way in determining if he'll play again this season.
"It's unfortunate for him, but he's home resting, trying to get comfortable," Lovullo said.
Quinn Roberts is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.