CM Punk is approaching year four of his mixed martial arts journey since announcing his UFC signing in late-2014, but the former professional wrestler has still only competed once: an infamous Sept. 2016 debut that ended with a two-minute rout at the hands of Mickey Gall.

But even at age 39, Punk isn’t backing down from the challenge.

The ex-WWE champion, whose real name is Phil Brooks, is expected to return for his sophomore Octagon appearance on June 9 at the United Center in his hometown of Chicago, Illinois for UFC 225. Punk’s opponent is rumored to be Mike Jackson, a part-time media member who also holds an 0-1 record in the UFC with a loss to Gall. And Punk’s teammate at Roufusport, former UFC lightweight champion Anthony Pettis, is confident that Punk’s encore performance will be better than the original.

“I see him every day, man. That guy’s in the gym every day,” Pettis said Monday on The MMA Hour. “He’s probably one of the hardest workers in the gym. He’s always there, always improving, and yeah, he’s definitely gotten better. You put that much time into [the game], you’re going to get better. He’s working the gi, he’s working no-gi. He’s training with top-level UFC guys inside his weight class, so I think we should see a better performance.”

Pettis said that Punk has been an omnipresent figure in the gym in Milwaukee, even immediately following his disappointing showing against Gall. Punk is determined to improve, he said, and that determination hasn’t wavered in the 18 months since UFC 203, even as the former wrestling superstar approaches his 40th birthday.

“He never stopped. Like, he didn’t take a break,” Pettis said. “He was right back at it. I think he had a couple injuries, but he was right back at it.

“It doesn’t surprise me. He’s a competitor, man. And he loves the grind. I don’t know what else he’d be doing if he wasn’t doing this. He’s just, he’s always in the gym. So in the short time I’ve known him for his first fight to this fight, it’s the same, the dude is just pushing hard, man. He’s grinding, he’s getting better, he’s putting the mat time in, and there’s no way around getting better besides putting the mat time in.”