NaVorro Bowman knows he's not back to 100 percent yet.

But the three-time All-Pro linebacker is certain that he will return to the form that made him one of the most intimidating players in football. All his surgically-repaired knee needs is a little more time.

"No doubt. No doubt," Bowman said on Friday after the San Francisco 49ers wrapped up their second week of OTAs. "The knee will get to where it needs to be. Maybe not as fast as you guys expect, but I'm definitely going to get back to that level."

Bowman is 16 months removed from sustaining a torn ACL in the 2013 NFC Championship game. The injury, of course, sidelined him for all of last year.

With more than three months remaining until the 2015 season kicks off, the 49ers are taking a cautious approach with Bowman in offseason workouts. Although the veteran took part in all three of the team's practices this week, Bowman's reps are being closely monitored.

"It hasn't been consistent," Bowman said of his knee. "I go out there some days, and I feel great and some days I have to fight through it. That's part of the process. I understand that. But mentally, it messes with me sometimes.

"Just to get out there and do something is always good for the knee. As long as I keep doing that, it'll get used to knowing that I want to get back out there playing football."

For now, Bowman is wearing a knee brace in practice – something the training staff insists on despite the linebacker's objections.

"I don't want to wear it, but I'm doing what the doctors are asking me," Bowman said, smiling. "It's just not letting me run as fast as I want to."

Asked what he'll do with the brace when the team informs him that he no longer needs it, Bowman said he "might just light it on fire."

The mental aspect of the rehab has been as difficult for Bowman as the physical side. Learning to trust his knee is still a work in progress but it's coming along slowly just as everything else in the recovery process.

"That's the biggest challenge," Bowman said. "I'm trying to go out there and execute and not pay too much attention to my knee because it is safe and it does feel good."

Bowman looked like his old self on one play in particular Friday. During team drills, the linebacker made a leaping grab in the end zone to snatch away a Colin Kaepernick pass away from Garrett Celek. Bowman's feet landed out of bounds, but the play had the entire team buzzing on the sideline.

"It got me back in the play-making mode," Bowman said.

When the team breaks for the summer in mid-June, Bowman will not be taking any time off from his rehab schedule. According to Bowman, there's too much at stake to put his work on hold.

"I'm a professional," Bowman said. "I have to enjoy my life, but at the same time, what we're facing in these next few months is way more important. The most important thing is getting my knee right and getting ready for my guys. I'll be working."

That type of attitude had Jim Tomsula close to a loss for words. The coach, like the rest of the 49ers, is pulling hard for the star linebacker to close out these final steps in his long-awaited comeback.

"It's NaVorro, first of all, so it's great having him back on the field, and also with the road he's traveled in the last year and a half," Tomsula said. "It's just awesome and great to see."