After Saturday night's game, Sheets dejectedly said his chances of pitching again this year were "pretty slim."

The Brewers' ace right-hander has a moderate tear of his right latissimus dorsi muscle and was placed on the 15-day disabled list before the team's 8-4 loss to Atlanta.

"Pretty slim, bottom line," he said. "Fifteen days of nothing. It doesn't matter if you're better after that or not. It might be better, might not. There are five weeks left in the season.

"You can come back for one meaningless start," he said. "I wish the game would be meaningful, and that's still very slim [that he would be ready to pitch]."

Sheets said he felt bad for fans and for teammates, since the team was playing well when he was injured.

"We're making a run," he said. "Not that they still can't. They can still make a run. I felt like I was helping a lot right now."

Since June 18, Milwaukee had won 10 of the last 14 games in which Sheets pitched. The team is 24-25 in games started by other pitchers during that span.

"I was throwing better than I have, maybe ever," he said.

Sheets also said he didn't know what caused the injury.

"I was in good shape," he said. "I don't know how you could prevent it. It seems like it could happen at any time."

Team physician Dr. William Raasch said the muscle heals with rest.

"The latissimus dorsi is kind of an important muscle for a baseball pitcher because it's the muscle that allows you to accelerate the ball," Raasch said. It's also the muscle that de-accelerates the arm after the ball is released. "

Sheets suffered the injury in the eighth inning Friday night. He underwent an MRI Saturday afternoon at a local hospital after arriving at Miller Park and complaining of soreness.

"I didn't think it would be real good," Sheets said of the test.

Raasch said the medical procedure showed more of a tear than what was expected.

"It was a little bit more than we anticipated given how comfortable he was after pitching Friday night," Raasch said.

Under the best case, Raasch said Sheets would feel no discomfort after 15 days and would undergo a second MRI. Otherwise, it could take two months for the muscle to heal, ending Sheets' season prematurely.

The Brewers are trying to post their first winning season since 1982.

"We're not going to just pack up and die," manager Ned Yost said. "Guys have to pick up Ben's slack.

"It happens to every Major League team in baseball. They get key injuries and they don't quit. They find ways to work around it. You hate it for Benny and you hate it for your team, but you pick up the slack and let's go."

Yost and general manager Doug Melvin said no decision had been made on who would take Sheets place in the rotation.

Reliever Justin Lehr was recalled from Triple-A Nashville to take Sheets' place on the roster.

It is the second time this year that Sheets has been placed on the disabled list. He missed time this spring with an inner ear disorder that left him feeling dizzy for weeks.