"His control has not been good," Leyland said. "And normally when you see a guy that had real good control early in the season all of a sudden kind of lost that control, there's usually a red flag there. There's usually a message there that something's not quite right."
Perry visited team physician Dr. Stephen Lemos in Detroit for an MRI exam on Monday, according to head athletic trainer Kevin Rand. The results showed a mild impingement around the back of his rotator cuff and some mild tendinitis around his biceps.
Perry tried to throw a bullpen session Wednesday afternoon. Had he come through that OK, he might've been available out of the bullpen Wednesday night.
However, Rand said, "He felt it on a few of his throws."
That's when they made the decision to shelve him and put him on a medication program.
"I don't really think this is anything long or serious, I really don't," Leyland said. "But at the same time, you have a red flag when you see the control."
Leyland does not believe this puts any extra pressure on any particular reliever. He did say earlier Wednesday, however, that he plans on using Joel Zumaya in shorter outings, usually one inning or less, in hopes of having him available more often.
That said, he doesn't expect this to be a long-term loss.
"I don't really think it's anything to fret about, I really don't," Leyland said. "I don't think it's anything serious at all. It's just matter of taking care of it, getting it quieted down, going back out and pitching a little bit, and hopefully coming right back here."
Gonzalez made an impression on the Tigers' staff with a strong Spring Training, but has spent the season in the Mud Hens rotation. His performance there, though, earned him the recommendation from the Minor League staff ahead of others in the Hens' bullpen.
The 27-year-old Gonzalez, signed as a Minor League free agent last winter, owns a 4-5 record and 3.46 ERA in 11 starts, striking out 53 batters over 65 innings while giving up 68 hits. His last four starts, in particular, have been stellar: 27 2/3 innings, 19 hits, six earned runs and 23 strikeouts, including a complete-game shutout of Indianapolis May 23.
"I always use the guy they recommend, so that's the guy we take," Leyland said. "And he has been starting down there, so he should be able to give us some innings."