USC defensive lineman Marlon Tuipulotu undergoes season-ending back surgery

USC pulled off its biggest heist of last winter’s recruiting cycle when it flipped Marlon Tuipulotu from his commitment to Washington with less than two weeks before signing day.

Tuipulotu was considered one of the best defensive linemen in the nation, and when he showed up in the spring he showed why. He was big, already almost 300 pounds, with refined technique and quick feet. He narrowly missed out on a starting spot and saw significant time early.

On Tuesday, coach Clay Helton announced that Tuipulotu’s season was done. The freshman from Oregon underwent season-ending surgery on his back Tuesday.

Tuipulotu played in three games this season, missing Week 3 with a knee injury and the final two games because of the back injury. The limited time means he will be eligible to receive a medical redshirt.

The back injury “was from maybe a previous injury at an early age,” Helton said. Pain flared up in the spring, and “as we went through the season he just experienced more and more,” Helton said.

USC telegraphed the move last week against Oregon State, when it chose to burn freshman Brandon Pili’s redshirt to insert him for significant chunks of the game at defensive tackle.

Helton does not expect Tuipulotu’s injury to linger.

“I think it’s something that they got fixed,” Helton said. “For the big picture it’s very, very positive for him. It was actually better than they thought and the future is very bright for the kid.”

Helton did not say what the specific injury was.

“I’m not a doctor,” he said. “It’s just a lower-back injury.”

Josh Fatu will continue to start at defensive tackle, with Pili and Kenny Bigelow Jr. as the reserves.

Darnold apologizes

Quarterback Sam Darnold said Tuesday that he apologized to USC’s coaches for comments he made after Saturday’s game that were critical of USC’s play calling.

“I can sense that defenses are focusing on tendencies of ours, so we’ve just gotta, I don’t know, we’ve just gotta run different plays out of different formations and motion some guys and get away from our tendencies a little bit,” Darnold said at the time. “And I think we’ll be fine if we do that.”

Darnold said that the coaches called him after becoming aware of the comments and asked for context.

“I told them that I was wrong, and I watched the film before they called me and just that I was blatantly wrong,” Darnold said.

He added: “For me to make a comment like that, it’s something I shouldn’t do. First of all because it’s not my place and second of all because I didn’t watch the film and I wasn’t aware of what was going on. I was just bummed about a couple of decisions that I made on the field and just kind of let my emotions get the best of me in that situation.”

Helton denied that Darnold apologized to him.

“I visit with Sam every Monday and it was a nice discussion and I’ll leave that between coach and player,” Helton said. “We have great players, great coaches and they’re doing a wonderful job together.”

Quick hits

Guard Viane Talamaivao underwent surgery Tuesday to repair the pectoral tear that ended his season. Helton was it was successful. … Tight end Daniel Imatorbhebhe (hip flexor injury) was a limited participant in practice for the first time since the season began. … Right tackle Chuma Edoga (high ankle sprain) did not practice Tuesday, but Helton said he is planning for Edoga to participate in practice Wednesday.

zach.helfand@latimes.com

Follow Zach Helfand on Twitter @zhelfand