"We'll reassess on Monday and see where we are for Chicago," said McCarthy, referencing the following game Dec. 18 against the Bears.
Perry leads the defense with a career-high eight sacks. The hand injury he sustained in the 21-13 win over the Houston Texans last Sunday will deny Perry from playing a full season for the first time in his five-year, injury-marred career.
"I feel terrible for Nick," McCarthy said. "He was having a great season, clearly his best season."
Perry's setback compounds what has been a short-handed bunch at linebacker in recent weeks.
The starting inside duo of Jake Ryan and rookie Blake Martinez have missed time because of ankle and knee injuries, respectively. Ryan returned to action against the Texans but aggravated his injury, though he was able to re-enter the game. Martinez has missed the last two games.
Veteran outside linebacker Clay Matthews has a separated left shoulder that limited his playing time and his effectiveness against the Texans.
Kyler Fackrell, a rookie who had been contributing as a backup at outside linebacker, has missed the last two games because of a hamstring injury.
"How we plan moving forward, frankly it's the same thing we do each and every week," McCarthy said. "It's based on the health of your team. Our job is to put players in position to be successful. We feel good about our plan and plan on being successful Sunday."
-- Even with a return to normalcy of having a Sunday game followed by a Sunday game, McCarthy had his players on an unusual schedule at midweek.
The team didn't practice Wednesday until the late afternoon.
"This is kind of part of our learning program," McCarthy said. "This is a different schedule that we're a part of with this long stretch of games (after having the bye in Week 4) and obviously what's going on with our medical report."
The players spent the early part of the day lifting and involved in other strength work, "just really trying to help these guys get their legs back," McCarthy said.