CINCINNATI — Closer Matt Capps will be sidelined for approximately eight weeks with a shoulder injury detected today, the fourth Pittsburgh Pirates pitcher to go on the disabled list in the last two weeks.

Capps blew save chances in the first two games of a series against the Cincinnati Reds, then flew to Pittsburgh on Wednesday for an MRI on his tender shoulder. The test indicated he has bursitis and tightness that prevents him from getting full extension during his delivery.

General manager Neal Huntington said the 24-year-old closer will go on a rehabilitation program for about four weeks, then take another four weeks to get back into pitching shape.

"We're going through a tough stretch right now," Huntington said during a conference call. "Matt's a gamer. We know he's going to be back."

The Pirates and the Reds hold the bottom two spots in the NL Central. Pittsburgh has been scuffling to try to keep its pitching staff intact during a series of injuries.

Pittsburgh has placed reliever Franquelis Osoria and starters Phil Dumatrait and Ian Snell on the 15-day disabled list in the last two weeks. Dumatrait has bursitis in his left shoulder, Snell has a sore right elbow and Osoria has bursitis in his right ankle.

The Pirates were one pitcher short of their normal complement for the final game of their series against the Reds on Wednesday night. They hadn't made a move to replace Capps' roster spot.

"The reality is, it's probably a very short-term move because we're looking at Phil Dumatrait and hopefully Ian Snell coming off the disabled list at some point here sooner than later," Huntington said. "So we're not looking at this as being a long-term replacement for Matt Capps."

Capps converted his first 15 save opportunities before blowing one on June 20. That started a rough stretch for the closer, who blew five of his last seven chances. Capps gave up a two-run, game-ending homer to Ken Griffey Jr. on Monday night, and failed to hold a one-run lead in the 10th inning on Tuesday.

Romulo Sanchez wound up getting three outs and his first career save in a 6-5, 11-inning win on Tuesday night. Damaso Marte also has saved a game this season.

Huntington said Capps doesn't have enough range of motion in the pitching shoulder, which could have resulted in a torn labrum if he had continued to pitch. No surgery is anticipated.

"Ninety to 95 percent of pitchers that have this sort of problem, when it's caught early like this, can go on a rehabilitation program, eliminate the range of motion deficit and go back and pitch healthy and pitch effectively," Huntington said. "And that's what we're anticipating with Matt."