Derek Carr sustained a groin injury late in the first quarter against the Los Angeles Chargers on Thursday night and did not return during the Raiders' 30-27 overtime loss.
The Las Vegas quarterback grabbed his groin area after running out of bounds on a scramble on third-and-goal and immediately went to the locker room.
Daniel Carlson came on and kicked a 23-yard field goal to cut the Chargers' lead to 7-3.
After the Raiders' crushing loss, coach Jon Gruden said Carr didn't sustain a torn groin, but the injury still is bad, calling it "significant," according to The Athletic's Tashan Reed
On the Raiders' second offensive series, former No. 2 overall draft pick Marcus Mariota came in for Carr and drove the team down the field for a go-ahead touchdown.
Mariota engineered a seven-play, 86-yard drive and capped it with 35-yard touchdown pass to Darren Waller.
Despite not playing all season, Mariota looked good. Unfortunately for the Raiders, it wasn't enough to pull out a much-needed win. The Oregon product went 17-of-28 for 226 yards and one touchdown. He did throw an interception late in the fourth quarter that ended a promising drive for the Raiders.
Mariota also carried the ball nine times for 88 yards and a touchdown. But he wasn't able to play the role of the hero. Fellow former Oregon quarterback Justin Herbert scored the game-winning 1-yard rushing touchdown to hand the Raiders their seventh loss of the season.
With the loss, the Raiders' hopes of making the playoffs took a severe hit. To have any chance, they will have to beat the Miami Dolphins next week and the Denver Broncos in Week 17. If Mariota indeed starts in place of Carr, he faces a tall task of getting Las Vegas to the postseason.