It's difficult to measure Khalil Mack's drive to excel this season, but it's easy to see.

At least that was the case Saturday when the Bears' star outside linebacker participated in a Zoom video call with the media while riding a Peloton bike in his home. Dripping with sweat, Mack candidly discussed his determination to rebound this season after not performing up to his own high standards last year.

"I wasn't good enough, wasn't good enough at all," Mack said. "I don't make any excuses. I just rise to the occasion, and I am getting ready for this one. It's going to be a fun one. Man, I can't wait."

Last season Mack was named to his fifth straight Pro Bowl after topping the Bears with 8.5 sacks and five forced fumbles and tying for the team lead with 5.0 tackles-for-loss. But it was the first time since his rookie season with the Raiders in 2014 that he failed to record at least 10 sacks. 

"The expectations that I have for myself, I definitely didn't reach last year," Mack said. "Only I can challenge myself and only I can tell myself what it was that I expected from myself. So it's just that type of mindset: challenging myself every week to get better, and that's all you can really live by."

Bears coach Matt Nagy doesn't think that pass rushers should be judged solely on their sack totals. Pressure on the quarterback that doesn't result in a sack can lead to other positive outcomes for the defense, such as an interception, incompletion or penalty for holding or intentional grounding.

"When you have a lot of sacks in your career like [Mack] does, that's what people evaluate off of," Nagy said. "But I can tell you first hand, from going against Khalil and other great pass rushers, we look for the sacks, but we also look to see, 'How much are you affecting the quarterback?' Every team that we play is going to have to game plan for him. You've seen that now for two years.

"The only thing that matters is, is Khalil ready to rock and roll? And he certainly is. Just from the talks and discussions, he's had an unbelievable offseason. He's very, very focused. He doesn't say much. He's not a guy that says a whole lot, which you like, you appreciate. It's who he is. He does his speaking on Sundays, on gameday. That's all we care about, and I know that he's really looking forward to this season."

Mack was acquired by the Bears in a blockbuster trade with the Raiders Sept. 1, 2018. He was named All-Pro and voted to the Pro Bowl in his first season in Chicago after leading the team with 12.5 sacks and a career-high six forced fumbles and ranking second with 10 tackles-for-loss. As he enters his third year with the Bears, the 6-3, 269-pounder is elated to be part of a talented defense that boasts Pro Bowlers at all three levels.

"I don't really see a ceiling for this group," he said. "Whatever we want, that's what we're going to get. It's just going to be about going out and having fun.

"I don't have anything to prove. I know myself. I know what I'm capable of. And this is going to be fun, man. I can't wait to get out there with my teammates and make plays and give oohs and aahs to the TV crowd. And all that that brings, it brings me joy, man. I love this game. It's fun. I don't stress over this game. But I love it and I just can't wait to get out there with my guys."