The San Francisco 49ers listed running back Matt Breida, who is tied for the NFL rushing lead with Ezekiel Elliott of the Dallas Cowboys, as questionable for Sunday's game against the Los Angeles Chargers because of a right knee injury.
Breida did not sound optimistic on Friday and his participation is expected to be a game-time decision.
"I've got to feel comfortable," Breida told the San Francisco Chronicle. "It's a long season."
Breida was limited in practice on Wednesday, went through a full practice on Thursday but was limited again on Friday. He is dealing with a hyperextended knee and calf soreness, according to head coach Kyle Shanahan.
"Just to see how he feels on game day," Shanahan said. "He's been up and down a little bit this week. He got a little bit more [Thursday]. We kept him limited [on Friday], just trying to manage the wear and tear.
"But questionable is better than doubtful, so hoping it works out."
Breida has rushed for 274 yards on 32 carries, an 8.6-yard average, and one touchdown in the first three games.
Complicating matters for the 49ers, backup running back Alfred Morris also is listed as questionable for the game against the Chargers because of a knee injury.
The 49ers ruled out guard Joshua Garnett (toe) and cornerback Richard Sherman (calf). Safety Jaquiski Tartt (shoulder) is doubtful and safety Adrian Colbert (hip) is questionable.