Two-word mantras guided Alex Singleton during his NFL career: Be tough. Never quit. Perfect attendance.

Entering his sixth season, the inside linebacker had not missed a practice. Then, on the eighth snap against Tampa Bay on Sept. 22, he tore the ACL in his left knee. He finished the game — play hurt fits in with the motto — and gave no indication of his injury in the victorious locker room.

An MRI ended his season. At the Super Bowl representing the Broncos as their Walter Payton Man of the Year nominee, Singleton provided a blunt assessment of life as a spectator.

“Miserable. I hated it,” Singleton told The Denver Post. “That’s why I couldn’t wait for the Super Bowl because it means next season is on the way.”

Singleton remains on pace in his recovery. He predicted he would be ready when the regular season starts, returning faster and stronger. At 31, he aims to regain the form that saw him average 104 solo tackles in his first two years with the Broncos.

“Everything is good. I started running. I am moving in the right direction, so I will be good to go when the season rolls around,” said Singleton, who is roughly five months removed from surgery. “It’s not definite for OTAs (which start in April). I will be participating. I will be there. That will be way more doctor stuff. But training camp, I will be 100 percent.”

Singleton plays with emotion, his hair flowing from his helmet as he is flying to the ball. The rehabilitation forced him to press pause and widen his lens.

“I learned that seasons are a lot longer than you think they are. It was really cool to see things from an outside view instead of just week to week. I got to see the culture change, got to see how guys went through the year. As a young team, I was able to observe how they did everything,” Singleton said. “It was nice to see that, learn that as a player, to have that going into this year.”

Cody Barton emerged in Singleton’s absence, posting 106 tackles and two interceptions. Yet, it remains possible the Broncos will seek more speed at the position for coverage purposes.

Watching the Eagles, his former team, win the Super Bowl has only strengthened Singleton’s opinion on the Broncos’ future — and specifically quarterback Bo Nix. He sees parallels with a certain Super Bowl LIX MVP.

“Bo’s been the guy now. It’s the hardest league to play in and that’s the hardest position to play. To do what he did this season is special, so now what is he going to be able to do in his second year? It’s going to be huge,” Singleton said. “With Jalen Hurts, I got to see what it was like from his first year to his second year. I am really excited for what Bo is going to do.”

While his season was cut short on the field, it did not change Singleton’s impact off it. He remained involved as an advocate for the Special Olympics, where his sister Ashley has been an athlete for two decades.

“It was the coolest thing ever (to be the Walter Payton nominee),” Singleton said. “This gives the Special Olympics and those athletes a bigger stage. I play football and we get this platform, but to be able to share this platform with them is what it is all about. To be able to talk about them and show off my sister and her friends and what they are accomplishing, it is really special.”