The Cleveland Indians could be without their closer Chris Perez to start the season after it was revealed that he will likely be sidelined four to six weeks with a strained left oblique.

The injury was discovered after he cut his first bullpen session short on Thursday due to what he originally thought was just a cramp.

Perez described the events to MLB.com, "I was doing what I normally do when I throw a bullpen. I felt a cramp, so I think I was a little dehydrated. It is what it is. I pulled it. I'm physically ready to go. I could play tomorrow if it was Opening Day and this didn't happen. I'm physically ready to go. It wasn't because I came in out of shape or anything.”

Perez’s injury comes on the heels of Friday’s announcement that outfielder Grady Sizemore could be lost for the first few weeks of the season after he suffered a strained lower back.

When asked if Perez would miss Opening Day, trainer Lonnie Soloff responded “I wouldn’t say that. We’ll have to see how things go and how he responds with his throwing sessions once he gets back on a mound.”

In his first full season as the Indians closer, Perez posted 36 saves, 3.32 ERA and a .210 average against in 64 games.

If he misses any regular season game action, manager Manny Acta’s most likely candidates to replace Perez would come from one of the following set-up men:

Vinnie Pestano (2.32 ERA, 1.05 WHIP, .184 AVG against and a 12.19 K/9 in 68 games)

Tony Sipp (3.03 ERA, 1.11 WHIP, .198 AVG against and a 8.23 K/9 in 69 games)

Sipp (24) and Pestano (23) both were among the top 10 American League relievers in the holds category and the Indians bullpen as a whole finished fifth in American League relief ERA (3.71).

Jim Pratt is a Featured Columnist covering the Atlanta Braves for Bleacher Report, MLB contributor for MLBDepthCharts and BravesWire. Follow Jim on Twitter, @2OutSacBunt