CHARLOTTE, N.C. (AP) — Baker Mayfield wore a walking boot on his left ankle after the Carolina Panthers’ 37-15 loss to the San Francisco 49ers and said he would have an MRI on Monday to determine the extent of the injury.

The former No. 1 overall pick struggled again Sunday, completing 20 of 36 passes for 215 yards with an interception that was returned 41 yards for a touchdown by 49ers cornerback Emmanuel Moseley. Mayfield has four touchdown passes and four picks in five games for the Panthers (1-4), who have lost 11 of their last 12 games under coach Matt Rhule.

Mayfield’s ankle got rolled up on late in the first half, but he returned to play in the second half, leading the Panthers to a touchdown on the opening drive of the third quarter. He remained in the game until the final few minutes when he was replaced with his team down by 22 points.

“Somebody landed on the ankle,” Mayfield said. “It didn’t feel too good.”

With Sam Darnold still at least a couple of weeks away from returning from his own ankle injury, P.J. Walker would be in line to start if Mayfield can’t play next Sunday against the defending Super Bowl champion Los Angeles Rams.

When asked if this is most trying time of his NFL career, Mayfield said, “I have a walking boot on, my leg is not cut off so I will be all right. I would love to be in a better position record-wise but you keep pushing forward. It’s not time to put your head down and give up.”