Twins center fielder Denard Span acknowledged he could be done for the season Thursday after landing on the 15-day disabled list because of a right shoulder injury.

Span is eligible to return Sept. 12, but after being diagnosed with a strained sternoclavicular joint Wednesday, Span was told it's an injury that won't fully heal until the offseason.

"Hopefully these next 10 days it'll heal enough to where I can finish the season off and start that healing process again during the offseason," Span said. "But I'm just going to listen to my body. ... I'm going to be smart when I come off the DL and do what I think is best."

Span has had pain in his collarbone area since Aug. 12, when he rolled awkwardly trying to make a catch. The Twins listed him as day-to-day, but he missed nine games before returning to the lineup. Then, after playing four games in five days, Span was scratched Tuesday and hasn't been available to play since.

Teams can expand their active rosters Saturday, but the Twins put Span on the DL so they could recall outfielder Matt Carson from Rochester on Friday. After batting .381 (8-for-21) in five games for the Twins, Carson was sent back to the minors Aug. 23, and players must spend 10 days there after being optioned -- unless the team has a DL situation.

"I had my bags packed [for Kansas City] and was ready to go on the road trip," Span said. "But I had a talk with [General Manager Terry Ryan], and we agreed that maybe it was just best to take a few more days to get some of the swelling out of the ligament that's swollen and see where I'm at in 10 days."

Span, 28, has played 108 games this year and was limited to 70 last year because of injuries. He's batting .286 with a .349 on-base percentage, so the Twins will miss their leadoff hitter.

But his absence will make it easier for them to get a look at Carson, Chris Parmelee, Darin Mastroianni and possibly one of their top outfield prospects from Class AA -- Aaron Hicks or Oswaldo Arcia -- if either becomes a September call-up.