The rookie linebacker wanted to know if he could address the team before the game. Nolan couldn't have been more pleased by the request.

Since Nolan took control of the 49ers in 2005, that role of team leader regularly had been filled by Bryant Young, who will play his final NFL game Sunday. And Young isn't the only 30-something veteran who might not be in the locker room next year.

Guard Larry Allen, 36, has said he will decide after the season whether to return in 2008. Defensive end Marques Douglas, 30, will be allowed to test the free-agent market in March, and linebacker Derek Smith, 32, might not be back, either. Brandon Moore filled in for Smith for much of the second half in Sunday's 21-19 win over Tampa Bay.

Even if Young, 35, is the only player who leaves, his absence will create a tremendous vacuum. For a decade, the reliable defensive lineman has anchored the 49ers' locker room. He is the player coaches count on to inspire teammates and the man teammates seek out for advice.

"Somebody else needs to step up and take that role," Nolan said during his news conference yesterday.

So it was appropriate that during Young's final game in San Francisco on Sunday, Willis set single-game career highs in tackles (20) and sacks (two). Nolan on Monday also lauded cornerback Nate Clements and safety Michael Lewis for their performances Sunday and said that they, too, will help fill the void left by Young.

Clements had a 62-yard interception return that set up the 49ers' third and final touchdown. Lewis, meanwhile, tied for second on the team with eight tackles.

"In the defensive meeting room, those are new guys from a year ago who will provide leadership as we go forward," Nolan said.

Of course, the 49ers also will be looking for someone to replace Young who leads the team with 6 1/2 sacks on the field.

Ronald Fields has been Young's primary backup at left defensive end this season, and Isaac Sopoaga, the one 49er who comes closest to matching Young's power, also has filled in at the position. Sopoaga, a former University of Hawaii star, is scheduled to become an unrestricted free agent in March.