Raiders quarterback Aidan O'Connell was carted off the field late in the third quarter of Las Vegas' 28-13 loss at Tampa Bay on Sunday with a knee injury.
O'Connell had his left leg placed in an air cast after coming down awkwardly following a seemingly late hit from behind by Buccaneers defensive tackle Calijah Kancey.
"It does not look good," Raiders coach Antonio Pierce said when asked for an update on O'Connell.
Pierce did say Kancey's push from behind appeared late, after watching the replay, and requested clarification in real time from the officials, to no avail.
"We asked, per usual," Pierce said. "We'll make a report, see what comes back on Monday or Tuesday."
Desmond Ridder, signed off the Arizona Cardinals' practice squad on Oct. 22, replaced O'Connell. He finished the game 12-of-18 for 101 yards.
The only other quarterback under contract with the Raiders is undrafted rookie Carter Bradley, who is on the practice squad.
O'Connell completed 11 of 19 passes for 104 yards with an interception against the Buccaneers.
The lone bright spot for the Raiders on Sunday was Brock Bowers, who set a single-season record for most catches by a rookie tight end. Bowers' reception with 27 seconds left was his 87th catch of the season, surpassing the 86 catches Sam LaPorta had for the Detroit Lions in 2023.
"He's having a great individual year," Pierce said. "Wish it could lead to more success with our team."
The Raiders fell to 2-11 with their ninth straight loss, marking their longest losing streak since they opened the 2014 season 0-10. Las Vegas next hosts the Atlanta Falcons (6-7) on "Monday Night Football" on Dec. 16.
Ridder said he was "excited" about the potential of starting next week against the Falcons, who drafted him in the third round in 2022 but released him this past August.
"Obviously, the team and the game that we're going to play next week is going to be big, and it's obviously a huge stage, but this team's excited," Ridder said. "This team's ready to just get a win, ready to put four quarters together, 60 minutes together, to be able to go out there and, at the end of the day, put up more points than the other team. How we do that, we've got to figure that out."
According to ESPN Analytics, the Raiders have a 16% chance at the No. 1 pick in the 2025 NFL draft, third highest in the league.