DETROIT -- Gary Sheffield and the Tigers hoped that a few days of rest might let the pain in his ailing right shoulder subside. On Monday, they moved to Plan B.

With little improvement in the shoulder since last week, but not enough, the Tigers placed their slugger on the 15-day disabled list. The move was made retroactive to Aug. 22, keeping him out for at least a week and a half.

Sheffield hopes to be back by then. He's hoping his shoulder improves enough that one more cortisone shot will get him back into playing condition. He has already taken two cortisone shots this season, and one more will put him at the limit for a single season.

"I just want to get it to the point where it feels OK strength-wise [before taking the shot]," Sheffield said. "You don't want to be shooting the last shot you can possibly get this year into an injured area and then it doesn't get [better]."

Though Sheffield said last week that he expected to miss at least the remainder of this homestand, he and Tigers officials had been holding out hope that it was a day-to-day injury. But as manager Jim Leyland pointed out, they couldn't go on any longer with a shortened bench.

"We had backup plans if this didn't work," Sheffield said, "because we have to do what's best for the team and from the overall standpoint of being short a player and the realistic part of me getting back onto the field. It came to the point where we can't just continue to wait on me when we're in the middle of a pennant race."

The shoulder has bothered Sheffield off and on for most of the summer. He missed a few days in late July before continued pain and numbness in his right hand forced him to miss close to a week in early August.

This is the first time this season Sheffield has been forced onto the DL, a major blow for a team that has had its share of injuries to overcome already this year. Sheffield has hit .279 with 24 home runs, 71 RBIs and 68 walks in 114 games. When he stole his 20th base earlier this season, the 38-year-old became the second-oldest player in history to post a 20-homer, 20-steal season.

That's a lot of offense to replace, as the Tigers' up-and-down scoring totals have reflected this homestand. It's enough of a loss that the team, which had been planning to go into September with the roster it had, is now looking at the trade market to see if there's any possible short-term fix.

"We're looking at all our options," Leyland said. "We don't have anything going. We haven't talked to anybody. But now you widen your scope."

Even so, they're not likely to find a bat that could come anywhere close to that production. At this point in the season, players must clear waivers in order to be traded, and star hitters are going to get claimed.

Or as Leyland put it, "Babe Ruth doesn't clear waivers."

When the Tigers needed a bat last September, for example, they ended up with Matt Stairs, the well-traveled designated hitter who became a spot starter against left-handed pitchers. Stairs, however, did not clear waivers, according to reports, so even that's not an option.

Further complicating matters, many solid players who do clear waivers are saddled with long-term contracts, something the Tigers don't want to plop onto their payroll.

"We're not going to get into any steep costs or anything -- that I can assure you," Leyland said.

For now, they'll handle the opening like they have for the last few days, using Marcus Thames in the outfield while rotating the DH spot between various players, including Thames, Magglio Ordonez and Sean Casey. Cameron Maybin is also likely to see some more time.

So will Timo Perez, who was recalled from Triple-A Toledo to take Sheffield's roster spot.