SANTA CLARA, California — After three years and six NFL games, San Francisco nose tackle Ian Williams finally got his first pro start.
It lasted less than a half.
During the defense's second series, Williams sustained a fractured left ankle, the result of a cut block from Seahawks right guard J.R. Sweezy that ended his season just as it was getting started.
The 49ers activated Williams from the active/physically unable to perform list on Tuesday and he returned to limited practice duties.
"It's been a long time. I've missed being here," Williams said Wednesday. "I'm excited about being back with the guys."
Williams, who was undrafted out of Notre Dame, will be looking to regain his stature with the 49ers, though he knows he will have to remain patient through the process.
"Early in the recovery I had some doubts," he said. "It takes time to get that out of the way. The training staff has put me through rigorous workouts and I know I still need to work myself back up."
San Francisco defensive coordinator Vic Fangio said there's no reason to rush him.
"He'll go through some individual drills and then we'll see how it goes," Fangio said. "If it's good, he'll continue to do more. If not, we can back off. The last look we got at Ian was Game 2. He hasn't taken a lot of regular season snaps, but last preseason he was playing well. We'll see how much he's back to that form."
His presence comes a few days after the 49ers allowed the Baltimore Ravens to rush for 237 yards in their preseason opener. That was without All-Pro defensive tackle Justin Smith and some of the other regulars who played sparingly.
Dorsey, who replaced Williams last year, is out indefinitely with a torn biceps. Until Williams returns to the rotation, the 49ers will rely on Smith, Ray McDonald and second-years players Quinton Dial and Tank Carradine.
"The biggest priority is to prepare the team for the regular season," Fangio said. "Everyone is getting a lot of reps. Guys have to be ready to play."
Williams said his biggest challenge is to get over the mental hurdle.
"Running around, making cuts, playing football, that's the easy part," Williams said. "As long as I feel good I'm going to push myself to see how far I can go. I know I can do more."
Rookie linebacker Aaron Lynch, who has been cleared to practice since Aug. 3, has been taking visual cues from guys such as Patrick Willis and Aldon Smith as he looks to make a smooth transition from defensive end to outside linebacker.
"When you watch the best, how they play, how they practice, I mimic them," Lynch said. "They practice the way they play. I came here to fit in. What do you want me to do? I'll do it."
NOTES: CB Tramaine Brock (sprained ankle) will miss Sunday's game against the Denver Broncos. Fangio hopes he'll be able to return to practice next week. "It seems like he's been out two weeks," Fangio said. ... Veteran CBs Chris Cook and Chris Culliver (knee) have been banged up and are being held back as a precautionary measure. "In the long run they will be fine," Fangio said. ... The 49ers signed LB Kion Wilson, who has played with the San Diego Chargers and Pittsburgh Steelers. He's appeared in 15 NFL games and started twice with the Steelers last year. ... The 49ers placed LB Blake Costanzo on injured reserve to make room for Wilson.