SAN DIEGO -- Wearing a brace on his left ankle, Chargers running back Ryan Mathews left the practice field Friday and gingerly made his way to the locker room.

Mathews has not practiced this week because of the balky ankle and is listed as questionable on San Diego's injury report for Sunday's AFC divisional playoff game against the Broncos in Denver. He had been a limited participant on Friday before playing on Sunday the past two weeks.

The change in routine seems to indicate that Mathews' ankle has gotten worse. He carried the ball just once in the second half of the Chargers' 27-10 wild-card win against the Bengals last week, finishing with 52 yards on 13 carries.

Mathews said the extra rest should help him, but he does not know if he will be cleared.

"The more rest you get, the better everything gets," he said. "It is only a week, so I'm just going to do what I can."

Mathews said he has been watching the team portions of practice so he can get accustomed to San Diego's game plan for Denver.

Quarterback Philip Rivers expects Mathews to do his best to get on the field.

"I'm not making predictions because I don't know where it stands honestly right now," Rivers said. "But he's going to do all he can to play, to give himself the best chance to play four quarters. You just never know how things are going to play out. But Danny [Woodhead] and Ronnie [Brown] are ready if they're needed more than usual."

The Chargers got better news on center Nick Hardwick, who cleared the NFL's concussion protocol and practiced as a limited participant Friday. He is listed as questionable for Sunday.

Hardwick is the only San Diego offensive lineman to start every game this season. If he can't play, Rich Ohrnberger would replace him in the lineup.

Right guard Jeromey Clary did not practice for a second straight day due to a shoulder issue and is listed as questionable. If Clary can't play, Johnnie Troutman would get the nod at right guard.