Niners lose top running backs

SANTA CLARA, California — The San Francisco 49ers still aren’t certain about the availability of their top two running backs for Sunday’s game against the Los Angeles Chargers.

Matt Breida, among the NFL leaders in rushing, and Alfred Morris both were limited in practice Friday and are listed as questionable. That’s an obvious concern for an offence preparing for its first full game without franchise quarterback Jimmy Garoppolo, who suffered a seasonending knee injury last week against Kansas City.

Breida hyperextended his right knee while planting to make a cut in the first half against the Chiefs. He returned later in the game, but the second-year back out of Georgia Southern hasn’t shown considerable improvement in practice since then.

“He’s been up and down a little bit this week,” coach Kyle Shanahan said Friday. “He got a little bit more [practice time Thursday]. We kept him limited just trying to manage the wear and tear. But ‘questionable’ is better than ‘doubtful,’ so we’re hoping it works out.”

Morris also is slowed by a knee injury. While he brings power running between the tackles, Breida is the game-breaking threat. His 274 yards are tied for second in the league with the Dallas Cowboys’ Ezekiel Elliott behind the Rams’ Todd Gurley.

But Breida has carried the ball just 32 times, giving him an average of 8.6 yards per carry that’s best in the NFL.