Pittsburgh Steelers linebacker T.J. Watt was placed in concussion protocol after the 2021 Defensive Player of the Year reported symptoms on Friday.

Watt played 51 of Pittsburgh’s 57 defensive snaps in Thursday’s 21-18 loss to the New England Patriots.

The five-time Pro Bowler inadvertently had his facemask collide with Patriot running back Ezekiel Elliott’s knee in the first quarter, and Watt was evaluated briefly on the sideline before returning.

Watt’s 14 sacks this season trail only Khalil Mack of the Los Angeles Chargers, who has 15.

Alex Highsmith, who emerged as a standout edge-rushing complement to Watt with 14.5 sacks last season, missed most of Thursday’s game after going into concussion protocol in the first half.

Inside linebackers Kwon Alexander and Cole Holcomb are already out for the year.

Veteran Markus Golden and rookie Nick Herbig are projected to be the starting edge-rushing combination in next Saturday’s game against the Indianapolis Colts if Watt and Highsmith remain in protocol.

Watt is a three-time All-Pro selection with 91.5 sacks and 189 quarterback hits in 100 career games.

The @NFL will routinely investigate issues like this. Blood in mouth is cause for head check. Reason for smelling salts has to increase index of suspicion. Dark visor has been used by #TJWatt before this season and the reason has to be documented and pre-approved by league. https://t.co/CeqP7aXjWj

— David J. Chao - ProFootballDoc (@ProFootballDoc) December 9, 2023