An illness kept Cobb from practice Wednesday.
"Important for him to practice," McCarthy said, via the Milwaukee Journal Sentinel. "Important to be outside. Randall took reps we set up for him. I think by game time he'll be fine."
Wide receiver Jordy Nelson also was back after he missed Wednesday with an ankle injury. He was limited.
"Jordy Nelson ran particular vertical routes, and I thought he looked pretty good," McCarthy said.
These two not being available Saturday would be a surprise. The Packers need all hands on deck against the 49ers' defense, and Cobb and Nelson combined for 14 receptions for 141 yards in the season opener against San Francisco.
Follow Kareem Copeland on Twitter @kareemcopeland.