Las Vegas Raiders quarterback Jimmy Garoppolo is reportedly in the NFL's concussion protocol following the team's Week 3 loss to the Pittsburgh Steelers, according to NFL Network's Ian Rapoport.

Garoppolo took four sacks in the 23-18 loss, and was hit a total of eight times by Steelers defenders. He was not available to speak to the media after the game, likely because he was already in concussion protocol.

It's unclear when Garoppolo potentially suffered the injury. Garoppolo took a number of big hits, one of which resulted in Steelers safety Minkah Fitzpatrick receiving a roughing the passer penalty.

Garoppolo laid on the ground for a few seconds following that hit.

Garoppolo stayed in the game after that, and threw a 1-yard touchdown pass to Davante Adams a few minutes later. He also led the team on another drive at the end of the game that resulted in a field goal. Garoppolo finished with 324 passing yards. He threw two touchdowns and three interceptions in the loss.

Through three games, the Raiders have been on the receiving end of a number of brutal hits. Receiver Jakobi Meyers missed the team's Week 2 game against the Buffalo Bills after suffering a concussion in Week 1. Adams took a similarly rough hit against the Bills in Week 2, but managed to avoid going into concussion protocol.

Kareem Jackson and Taylor Rapp each received fines for those hits. Fitzpatrick could also receive a fine following his hit on Garoppolo in Week 3.