The Tribe recalled left-hander Nick Hagadone to fill Perez's spot in the bullpen.
Through eight appearances for Cleveland this season, Perez struggled to find the strike zone and feature the same velocity he has shown in the past with his fastball, slider and changeup. The 29-year-old missed time during Spring Training due to soreness in his left shoulder, but he made the Opening Day bullpen after logging just five Cactus League innings late in camp.
"His stuff has been down a little bit," Indians manager Manny Acta said earlier this week. "He missed a lot of Spring Training. His velocity has been down."
This season, Perez has averaged 82.3 mph with his slider (the pitch he throws most often) and 87.7 mph with his fastball, according to PITCHf/x data. The slider stood at 85.7 mph in 2011 and 86.6 mph in '10. Perez averaged 89.3 with his fastball last season and 90.7 mph in '10.
On the season, Perez has also thrown just 55 percent of his pitches for strikes, compared to a 65 percent rate for his career. In his most recent outing, against the Royals on Wednesday, the lefty issued two walks in one inning, registering only four strikes among the 16 pitches he threw.
According to the Indians, Perez sufferd his lat injury during that outing.
Perez, who had never previously been on the disabled list in his seven big league seasons, has posted a 3.52 ERA in eight outings, compiling four strikeouts against four walks in 7 2/3 innings. He will be eligible to be activated from the 15-day DL on May 11.
Hagadone returns to the Indians for his second stint with the club this season. He was previously with the Tribe from April 17 through Sunday, while shortstop Asdrubal Cabrera was on baseball's bereavement list. Hagadone posted a 2.70 ERA in three relief outings for Cleveland and has also spun 7 1/3 shutout innings for Triple-A Columbus this season.