SANTA CLARA, Calif. — NaVorro Bowman is no longer just San Francisco’s other inside linebacker, or the inexperienced young guy. Teamed with Patrick Willis, he gives the 49ers one of the most feared linebacking tandems in the NFL.

Opposing offenses that try to focus Willis find they must also reckon with Bowman. The second-year pro out of Penn State has made huge strides for an attacking defense that is tops in the league at stopping the run and hasn’t given up a rushing touchdown this season.

Bowman’s rise as a replacement for the departed Takeo Spikes has meant so much for the playoff-bound 49ers (10-3). They’ve also gone 35 straight games without allowing a 100-yard rusher. Bowman’s team-leading 113 tackles are a significant jump from his 46 in 2010.

He loves working alongside Willis as part of one of football’s best duos.

“It is a huge accomplishment, a huge title that we can run with, but we don’t feed into those things,” Bowman said. “We just play our game out there, play within the scheme and make plays that are our plays to make. Me and Pat, we think of ourselves as one of the best and we have to keep going out there and proving it.”

“The way NaVorro’s playing, just the pure production to be in there and making all those tackles — and doing it game-in, week-in, week-out — for a second-year guy, first year starting, obviously he’s doing really well,” quarterback Alex Smith said. “I think we all understand that. He’s playing at a really high level right now, and the guy works really hard. He’s humble and obviously really talented.”

Just when many figured the 49ers were doomed when they lost Spikes after the lockout, Bowman has come up big time and again.

“He’s had a tremendous impact. Almost from the first day of camp until now, he’s really played well for us,” defensive coordinator Vic Fangio said. “He’s been an important player for us and I can’t say enough good things about him. Now’s the time though, where he’s got to put the pedal to the metal and finish these last weeks with even better play.”

Notes: Willis wasn’t in uniform for Thursday’s practice and neither was LT Joe Staley, who has a head injury and hasn’t been medically cleared for anything but walk-throughs.