The outfielder had an operation on his left hand on Tuesday. He injured his throwing hand when he smashed it against a door between the dugout and Red Sox's clubhouse after grounding out in the eighth inning to end a 0-for-4 night.
The club placed Sweeney on the disabled list before Tuesday's game against Detroit and recalled outfielder Ryan Kalish from Triple-A Pawtucket.
Will Sweeney be able to return before the end of the regular season?
"It's going to be close from what I gather," said manager Bobby Valentine. "He'll be out for a while."
Sweeney is not the first player to take out his frustration on an object off the field, though Valentine was disappointed in the result.
"Boys will be boys and the door that he happened to hit is dented, so it wasn't the first time, and he just must have went at it in the wrong direction. It has multiple whacks to it," Valentine said.
The manager was asked if he talked to his players about controlling their emotions to avoid an injury of this nature.
"I don't think I ever had a specific meeting about it," Valentine said. "It probably falls under the category of knowing the difference between right and wrong and check in the right at the door and leave the wrong behind you."
General manager Ben Cherington was also dismayed by Sweeney's actions, though he hadn't spoken to the outfielder as of Tuesday.
"Disappointing in how it happened," Cherington said. "I know Ryan feels badly about it. Ryan's been a good teammate and a good guy in the clubhouse. He's played hard all year and played through some injuries early in the year when we needed him to. I don't want to make more out of it than what it is, which is a mistake. Until I get a chance to talk to him about it, I don't want to say more than that."
Sweeney is hitting .260 with no home runs and 16 RBIs in 63 games this season. It is his third trip to the DL. He missed six games with a concussion in late May and 18 games with left big toe inflammation after going on the DL June 16.
Kalish is back in Boston for the second time this year. He hit .217 with no home runs and five RBIs in 18 games when Sweeney was on the DL for the second time.
"I'm ready to play, ready to help the team and get us some wins," said Kalish, who hit .307 with four homers and 12 RBIs in 17 games for Pawtucket. "I slept last night, which I didn't do the last time I came up. I'm here to take care of business and prove to everyone that I can stick here."