CLEVELAND -- The hits keep on coming for the Indians. Just not the kind they were hoping for.

Cleveland placed right fielder Shin-Soo Choo on the 15-day disabled list Sunday -- retroactive to Saturday -- with a right thumb sprain that will likely keep him out of action until September and potentially require surgery.

Choo sustained the injury diving for a fly ball in the eighth inning of Friday's 3-0 loss to the Athletics at Progressive Field. He underwent an MRI on Saturday, the results of which revealed more damage than originally anticipated.

"It's obviously more serious than we thought," Indians manager Manny Acta said. "When something like that happens, you think it's only going to be a day or two. He didn't feel much pain [Saturday]."

Sunday's news changed that.

"We don't know if it's season-ending yet, but surgery is possible," Acta said. "If he does come back, it could be the last month of the season."

Choo, seen wearing a protective wrap on his right hand Sunday morning, will be evaluated by specialist Dr. Tom Graham on Tuesday. He joins shortstop Asdrubal Cabrera and center fielder Grady Sizemore on the DL.

"I've dealt with injuries before in this job, but this is kind of weird, because those are our three best players," Acta said. "Nobody is feeling sorry for us. Other guys have to step it up."

The Indians recalled outfielder Michael Brantley from Triple-A Columbus on Sunday to assume Choo's spot on the active roster. Brantley will step in as the Tribe's everyday center fielder and leadoff hitter.

"We have to move on with the young kids," Acta said. "Now, we don't have to wait until Spring Training to see what these guys can do. It will give us more clarity."

Choo, the top candidate to represent the Tribe in the All-Star Game on July 13 before Friday's injury, leads the team in batting average (.286), home runs (13), RBIs (43) and on-base percentage (.390).

"I feel sad for the kid," Acta said. "It's tough for the club, but mainly for him, because he was having a good season."

Starter's role gives opportunity to Brantley

CLEVELAND -- Michael Brantley hopes his third stint in the Major Leagues is his last.

The Indians recalled the 23-year-old outfielder from Triple-A Columbus on Sunday, a move made necessary after the team placed right fielder Shin-Soo Choo on the 15-day disabled list with a right thumb sprain.

With Choo likely out until September, Brantley will have an extended opportunity to prove himself at the Major League level.

"He's going to play center field and lead off for us pretty much every day," Indians manager Manny Acta said.

A September call-up last season, Brantley made the Tribe's 2010 Opening Day roster, but played just nine games for Cleveland before being optioned to Columbus on April 19.

"I went down there and worked real hard," said Brantley, who started in center atop Acta's lineup Sunday. "I wanted to improve on all aspects of my game, from making reads in the outfield to swinging in the batter's box. I wanted to make sure I got comfortable in all aspects, so that when I came back, I could stay for a little while.

"I went in with the right mindset: to go out there and work hard each and every day on my game. As long as I do that, I know I'll be all right."

Brantley batted .315 (76-for-241) with 47 runs, nine doubles, two triples, three home runs, 26 RBIs and 11 stolen bases in 59 games for the Clippers, numbers that landed him an International League All-Star selection earlier this week.

He'll gladly forego the Triple-A All-Star Game for an everyday role with the Indians.

"It's always exciting to be back in the Major Leagues," Brantley said. "I worked very hard in Triple-A to get back here. I'm happy and ready to go."