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.