"Looks good," said head coach Pat Shurmur. "He's getting better every day,"
Shurmur wouldn't say whether Mack would be available to play Sunday at Oakland, only that he was improving.
Mack showed up at practice October 3 with symptoms of appendicitis and had surgery later that day, but didn't miss a game because Cleveland had a bye last week.
The 25-year-old center has started all 36 games for the Browns in three NFL seasons.