Jon Christenson's return from a compound leg fracture wasn't only a feel-good story for the Gophers. He was back for his senior year, as an instrumental part of their offensive line.

But the left guard suffered a right knee injury last week at Colorado State and needed arthroscopic surgery Monday.

"We're hoping to get him back possibly in … three to four weeks," coach Jerry Kill said Tuesday.

Fellow senior Joe Bjorklund, who started seven games last year, replaced Christenson at left guard.

"It's a shot to the gut," offensive coordinator Matt Limegrover said of Christenson's latest injury. "Any of the 120 kids that you have in the program, when something goes wrong — but for a kid like that that just keeps fighting back and keeps getting punched in the face — it's something that you pull a little bit harder for."

Other injury updates

• Kill said two other starting offensive linemen would be held from Tuesday's practice because of injuries. He didn't give names but said the hope is that both could be ready for Saturday's game against Kent State.

Christenson

• Wide receiver KJ Maye, who was spitting blood at Colorado State, was scheduled to wear a green nonparticipation jersey at Tuesday's practice. But Kill said Maye would be able to play against Kent State as long as he doesn't have a setback.

• Kill said safeties Damarius Travis (hamstring) and Ace Rogers (knee) are doubtful for Saturday's game.

• Redshirt freshman receiver Jeff Jones is having tests done on his injured ankle.

Gentry's debut coming

Kill said the Gophers would ease Isaiah Gentry back at practice from his hamstring injury. But barring a setback, the Cincinnati Moeller graduate will make his much-anticipated college debut Saturday.

"He's a guy that in all honesty, if he's healthy and he's right, he can help turn the game around," Limegrover said. "He's a big-play receiver.

"At times, I think you're guilty of pushing a kid because you want to get him back and they are not quite ready. I give Coach Kill and our training staff a lot of credit. They resisted the temptation to try to bring him back early. Wanted to make sure, it wasn't a little bit of good and then have a huge setback again.

"They waited extra long, so we have been champing at the bit as coaches to get him back involved. And now that he's gotten a clean bill of health, I'm excited to see him run around and do things. What he does [Tuesday through Thursday], as with any of them, gives us an idea of how involved they can be in the game plan."