Dennis Gardeck, who hurt his knee during the final drive of the Cardinals' last win in 2020, is undergoing surgery to repair a torn ACL.

The linebacker revealed the news himself on his Instagram account, saying the surgery would take place Tuesday. It would put some doubt on Gardeck's availability at the beginning of the 2021 season, depending on the speed of his rehab.

While it was suspected Gardeck had suffered a torn ACL, coach Kliff Kingsbury had declined to get into specifics of the injury. Gardeck, a standout special teams player, had a breakout season as a pass rusher despite only playing 93 defensive snaps all year.

Gardeck finished with seven sacks, second on the team to Haason Reddick's 12½ and a godsend to a team that was in deep trouble once All-Pro pass rusher Chandler Jones was lost early in the season to an elbow injury. He had never played an NFL down on defense until Jones suffered his injury in Week 5, coming in during that game in New York against the Jets and getting two sacks.

Gardeck was named a Pro Bowl alternate on special teams in 2019, and this season earned an All-Pro vote as a special teams player.

"I'll be back and better than ever in 2021, believe it!" Gardeck wrote in his social media post.

Gardeck is a restricted free-agent-to-be, but he is a player the Cardinals are expected to keep.