Panthers coach Ron Rivera says Pro Bowl fullback Mike Tolbert has a hairline fracture in his right leg and running Jonathan Stewart has a severely sprained right knee, adding to the team's mounting injury problems in the backfield.

Rivera says Tolbert won't play Sunday at Baltimore and will be reevaluated on a week-to-week basis, while Stewart will be reassessed on Friday.

Both injuries were sustained in Carolina's 37-19 loss to the Steelers on Sunday night.

The Panthers were already dangerously thin in the backfield with running backs DeAngelo Williams and Fozzy Whittaker both held out Sunday night because of hamstring injuries.

Carolina's running game ranks 29th in the league, averaging just 72.3 yards per game on the ground.

Richie Brockel is expected to start at fullback against the Ravens.

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