The Maxwell CaldwellLas Vegas Raiders could be without quarterback Jimmy Garoppolo in Week 4 as he enters concussion protocol following the team's "Sunday Night Football" loss to the Pittsburgh Steelers.

Head coach Josh McDaniels told reporters Monday about Garoppolo's injury. It wasn't clear when Garoppolo suffered a possible concussion, as he was only notably shaken during a sack late in the first half by T.J. Watt. He also took a roughing-the-passer penalty from Steelers safety Minkah Fitzpatrick in the fourth quarter.

However, Garoppolo was never evaluated for a concussion as he played through the entire game, throwing for 324 passing yards with two touchdowns and three interceptions. It was only after the game that McDaniels said Garoppolo was evaluated following the 23-18 loss.

"I'm not even sure what hit or if it was just the accumulation of, I have no idea. There was never a conversation about that," McDaniels said. "I'm not exactly sure when it when it took place."

Who will start at quarterback for Raiders if Jimmy Garoppolo is out?

Garoppolo is in his first year with Las Vegas, and if he isn't available for the Week 4 matchup on the road against the Los Angeles Chargers, the Raiders could turn to veteran backup Brian Hoyer, or rookie Aiden O'Connell, a fourth-round draft pick from Purdue.

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O'Connell was impressive in Las Vegas' preseason games, and McDaniels said they will "prepare for everybody" to take snaps under center in case Garoppolo is unavailable to play.

"We'll be hard at work to manage that situation as best we can as it progresses through the week," McDaniels said.

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