Pollard injured his left leg during a second-quarter drive as the Cowboys looked to score before halftime. After the game, ESPN's Todd Archer reported that he fractured his fibula and will require offseason surgery.
With 1:36 remaining in the half, Pollard caught a short pass from Dak Prescott on second-and-2 then turned upfield for an 8-yard gain. 49ers safety Jimmie Ward tackled him, and Pollard's ankle rolled violently under Ward's body.
Pollard needed help to a sideline medical tent and soon left the field on a cart with a towel over his head.
He was fitted for an air cast before he left the field and ruled out at halftime with an ankle injury.
The Cowboys didn't immediately provide further details of his diagnosis or confirm the report postgame. The drive ended with a Prescott interception that set up a 49ers field goal to take a 9-6 lead into halftime.
Pollard, 25, emerged in 2022 as the Cowboys' most effective running back in his first Pro Bowl season while sharing snaps with longtime starter Ezekiel Elliott. He led the Cowboys in the regular season with 1,007 rushing yards on 5.2 yards per carry. He added 39 catches for 371 yards while tallying 12 total touchdowns.
His injury is a difficult blow as he enters the offseason without a contract. He was in line for a big payday at the conclusion of his four-year, $3.2 million rookie deal.