Perez logged 16 pitches in the eighth inning of Cleveland's 8-2 loss to Kansas City and registered only four strikes in the process. He did, however, induce an inning-ending double-play groundout to sidestep any damage.
Perez's struggles also include a significant drop in velocity.
Entering Thursday's game, the 29-year-old left-hander was averaging 82.3 mph with his slider (the pitch he throws most often) and 87.7 mph with his fastball, according to PitchFX data. The slider stood at 85.7 mph in 2011 and 86.6 mph in 2010. Perez averaged 89.3 with his fastball last season and 90.7 mph in 2010.
For the season he has posted a 3.52 ERA in eight outings, compiling four strikeouts against four walks in 7 2/3 innings.
He missed a few weeks early in Spring Training because of soreness in his left shoulder.
"His stuff has been down a little bit," manager Manny Acta said. "He missed a lot of Spring Training. His velocity has been down, but he was able to make a pitch [on Wednesday night] and get that double play and work himself out of the inning. But he was off."