Sweeney had been out with a concussion, but he passed all the requisite tests to be activated on the first day he was eligible to return.
And once Sweeney stepped into the batters' box, he proved he was fine. Sweeney belted a double off the wall in center in his first at-bat and finished the game 3-for-4 to raise his average to .325.
"I got right back into it," said Sweeney. "My body is a little tired right now just because I haven't played in a week, but other than that, everything feels great. I wasn't trying to do too much up there."
Sweeney thinks that the new seven-day DL that has been instituted specifically for concussions is a good thing.
"I've never had a head injury, but I think it's a good idea, especially for guys like me who maybe had a mild one and don't need to go on the 15-day DL, that you can maybe have seven days to get back to where you were before and not feeling a little bit goofy, so you can get that seven days to get back to where you need to be and to get back in the lineup," said Sweeney.
To make room for Sweeney on the roster, the Red Sox optioned Che-Hsuan Lin to Triple-A Pawtucket.
Sweeney has also played well defensively, rotating between center and right.
It appears Sweeney will get more time in center now that Adrian Gonzalez is getting a lot of his playing time in right field.
But manager Bobby Valentine expects Sweeney will play right on Tuesday, as Kevin Youkilis or Will Middlebrooks is likely to get a day off against Detroit ace Justin Verlander.
Darnell McDonald should also return to the mix soon, as he played his third rehab game for Triple-A Pawtucket on Monday.