In a corresponding transaction, the team placed cornerback Robert Jackson on injured reserve with an ankle injury.
Njoku, who is in his third season with the Browns, has been sidelined since Week 2 when he suffered a broken wrist and a concussion on a borderline cheap hit by New York Jets cornerback Nate Hairston. Njoku was originally hoping to avoid surgery on his wrist, but later opted to have it repaired so that he could return this season.
The Browns designated Njoku to return from injured reserve on November 20 and had 21 days to activate him or he would return to the injured reserve list for the remainder of the season.