49ers RB Matt Breida sprains ankle in loss to Cardinals

SANTA CLARA, Calif. -- San Francisco 49ers running back Matt Breida sprained his left ankle in the first quarter of Sunday's game against the Arizona Cardinals and did not return despite his best efforts to get back on the field.

After the Niners' 28-18 loss, Breida departed with his left foot in a walking boot but said he was optimistic about his injury, noting that the initial tests showed no serious damage. But Breida also said he was scheduled to have more tests Monday morning to determine the severity of the sprain.

"I didn't know what happened at first," Breida said. "It was nothing too serious. It was just a little tweak. I have been battling through injuries the past two weeks. I was just trying to get out there and play. I will be all right."

Earlier in the day, Breida had done his best to get back into the game. Moments after the injury, he had both ankles taped up, did some jogging in place then did some running down the sideline before he shut it down and made his way to the locker room.

Breida said after the game that he simply didn't feel he could play close to his usual level with the injury, and that his presence would not have helped the team. His absence, of course, didn't help after he'd opened the game with eight carries for 56 yards and caught a 5-yard touchdown pass on the Niners' opening drive.

"If Breida can't go back in the game then no one can go back in the game because he works as hard as anyone at that," coach Kyle Shanahan said. "He's been one of our better players and obviously when he's not in there, it's definitely not easier."

With 30 seconds left in the first quarter and first-and-15 from the Niners' 41, Breida took a handoff and darted off right tackle, where he was met by Cardinals safety Budda Baker. As Breida attempted to cut back to the left, he stumbled and went to the ground, where he immediately reached for his left ankle.

Breida appeared to be in serious pain as medical staff rushed to his side. A couple of minutes later, Breida hobbled to the sideline with the help of Niners trainers and fullback Kyle Juszczyk. The 49ers officially ruled Breida out just after halftime.

Entering Sunday's contest, Breida was third in the NFL in rushing yards (313) and first in yards per carry (7.63). After departing, the 49ers turned to Alfred Morris for most of the workload, though third-string running back Raheem Mostert also stepped in and fumbled on his first carry.

Morris finished with 18 carries for 61 yards with three catches for 30 yards and Mostert had five carries for 11 yards with that fumble, which Arizona turned into a touchdown.

"It definitely hurt," Juszczyk said. "Matt is one of our best playmakers, extremely explosive. And when you lose a guy like that, that you are not anticipating losing him, it makes things definitely tough and other guys have got to step up. It's just something that maybe we didn't step up enough today."