SANTA CLARA Nnamdi Asomugha seems like the obvious choice to replace injured Chris Culliver at cornerback, but 49ers defensive coordinator Vic Fangio on Friday said "the jury is still out" on the veteran cornerback.
"He's had some good days out here and some days where we weren't sure if he was going to be able to still have it," Fangio said. "So I think we're kind of in between with him right now. Hopefully he'll be able to still have gas left in the tank to be able to go out and play like he did prior to going to Philadelphia."
Fangio said Asomugha will be part of a competition to replace Culliver, who suffered a torn ACL while covering a punt Thursday and will be lost for the season.
The last two seasons, Culliver has been the team's No. 3 cornerback, which has become a major role as NFL offenses increasingly use three or more wide receivers. Culliver took part in 63 percent of the 49ers' defensive snaps last season.
Three-year veteran Tramaine Brock mostly filled in for Culliver on Thursday, while Asomugha stepped in during Friday's practice.
Brock was the team's No. 3 cornerback when the 2011 season began, and he had two interceptions to start that season. But he broke his hand in Week 2. Culliver then a rookie stepped into the nickel role in Brock's absence and never gave up the job. Now Brock has a chance to win it back.
"Good quickness, good speed, good ball skills," Fangio said of Brock. "Now it may be a chance (for him) to go out there, show what he's got and take this job."
Tank's return When will second-round draft pick Tank Carradine start practicing? Fangio said he didn't know, but that it wouldn't be soon.
Carradine is recovering from an ACL tear suffered last season at Florida State. He and fellow rookie defensive lineman Quinton Dial, who is recovering from a toe injury, have been rehabilitating on a side field during practices.
Fangio was skeptical about how much each could contribute when they finally are cleared to practice.
"Yeah, they might be physically cleared to do that and physically able," he said. "But to think they're going to be as good as they were had they had all of this work I think is pretty naïve."
Injuries Defensive end Justin Smith sat out practice with one of his fingers wrapped, but he does not appear to be seriously injured.
Neither does starting cornerback Tarell Brown, who was on hand for the start of practice but did not finish it.
Starters Patrick Willis (hand), NaVorro Bowman (groin), Aldon Smith, Culliver (knee) and Jonathan Goodwin also missed practice.