For all the mayhem he has encountered trying to clog up the middle of Penn State’s defensive line and stop the run, 326-pound tackle PJ Mustipher always has risen to his feet ready to fight another play.

Only this time, he didn’t. The fans were still settling into their seats at Kinnick Stadium when Mustipher did his part to stuff the Iowa runner for a 1-yard loss near midfield, but could not get up.

Five plays into the Nittany Lions’ showdown against the Hawkeyes, Mustipher suffered a left knee injury that would sideline him for the season, a crippling blow not only to the Lions’ style of play, but also to their morale.

“I’ve been fortunate pretty much my entire life to be healthy,” Mustipher said Tuesday in his first media interview since the Oct. 9 injury. “I’ve never put myself in that situation. So when it happened, I was a little numb at first. I didn’t really know what was going on, what life would be like, how much it would change for me. So I really wasn’t sad, I really wasn’t mad. I was just like taking it all in.

“But it was tough. I think the first month of the injury was definitely challenging for me just adjusting to not playing football, the game I love. But I’m in a good space now. I’m in a good place. I’ve been working, I’ve been rehabbing. Being with the guys definitely helps a lot, too, being out at practice, in the locker room, and stuff like that. So I’ve been doing a lot trying to stay involved as much as possible, and keep my mind off the injury.”

Mustipher, who has played in 40 career games, seems to be doing a good job in that aspect. Shortly after his injury, he could be seen riding a little cart around the practice field and staying involved with his teammates, offering advice or encouragement.

But the senior, who was his typical expressive self on his Zoom call this week, admitted that it’s been difficult to keep a positive attitude not being able to play.

“It’s definitely tough, man,” he said. “I’m not gonna sit here and lie to you saying it’s easy to always be upbeat. I think this injury for me, it’s been more mental than physical. I can do the physical part. I can put the work in each and every day. But having that mental awareness and having that mental strength each and every day when you’re not out there doing what you love is hard.

» READ MORE: Penn State football coach James Franklin agrees to terms of 10-year, $75 million contract

“When I’m around my teammates and coaches, when I’m in the building or I’m outside the building with my guys, that’s when I feel better. I’m not worried about anything else but supporting them. And they’re supporting me, and I definitely appreciate that.”

Defensive line coach John Scott Jr. called Mustipher “the rock in our room and our football team.”

“Just having that guy around speaks volumes. He’s got the utmost respect. This is the same guy that, after the injury, was supporting his guys. He couldn’t stand up but was leading the charge. So having him around — and he’s here every day — is such a big deal for us. The guys depend on him. He just does so much.”

Mustipher’s typical day starts with classes followed by about 60 to 90 minutes of rehab, plus a weightlifting session of about the same length. Then he heads to the Lasch facility to help his teammates where he can.

“I’m not really preparing for anything,” he said. “When I’m on the practice field, I’m letting them know what I’m seeing as far as what they’re doing. If they have any questions, they can always come and ask me: What am I seeing? What can they improve on?”

Mustipher, who declined to give specifics about the length of his rehab, has an extra year available to him as provided by the NCAA because of last year’s pandemic. He called himself “fortunate” to have that option but added that he has made no plans, and will speak to his parents after the season ends to discuss his future.

For now, he looks forward to helping his teammates on the field, especially the development of the Lions’ other defensive tackles — Derrick Tangelo, Coziah Izzard, and Dvon Ellies, all Maryland natives like himself — and to viewing the game from a new perspective.

“I get to see it from a different aspect,” he said. “Not too many chances have I been able to take a step back from the game of football and see it from this view. So it’s different, but at the same time, I know everything happens for a reason.”