When the injury first happened, the Gophers couldn't help but wonder if offensive lineman Jon Christenson would ever play football again. On Nov. 2, 2013, the Minnetonka native broke both the tibia and fibula in his left leg at Indiana.

Christenson had a long steel rod inserted into middle of his left leg -- and somehow managed to return to play 12 games last season. He played mostly on special teams, but started at right guard in the Citrus Bowl. In February, he finally had the rod removed from his leg.

Heading into his senior season, he's "rod free," as offensive coordinator Matt Limegrover said. Christenson isn't practicing this spring as he rehabs the leg, but the Gophers are counting on him as a potential starter at either center or guard for this fall. He has made 16 career starts, switching between guard and center.

"He’s one of the smartest kids I’ve ever coached," Limegrover said. "He will do whatever he needs to, to be ready to go, and he’s also a fifth-year guy. So I’m not worried about him not playing. And the big thing is, I want him feeling healthy and feeling good. He never felt healthy a single day [last] fall. He still came every day and gave everything he had.

"I think he’s one of the toughest guys I know. What he tried to do and what he did every day with that rod in his leg -- I mean, he’s got to feel like a million bucks, the fact he doesn’t have it in there."

It'll be interesting to see how things shake out in August. The first-team offensive line this spring has been LT Ben Lauer, LG Joe Bjorklund, C Brian Bobek, RG Josh Campion and RT Jonah Pirsig. The coaches have been very pleased with Bobek, but Connor Mayes has had a hard time snapping the ball as the second-team center.

Mayes, who played guard last year as a true freshman, could be the starting center in 2016 after Christenson and Bobek leave. So it makes sense that the coaches want to give Mayes lots of practice snapping the ball this spring. The starting center this fall could be the 6-2, 297-pound Bobek, the 6-5, 320-pound Mayes, or the 6-4, 296-pound Christenson. And the starting left guard could be the 6-5, 296-pound Bjorklund, Christenson or Mayes. Other candidates include the 6-2, 310-pound Isaac Hayes and the 6-4, 311-pound Tyler Moore.

Limegrover said those decisions will play out over time.

"I tell them every day that they better get up every day knowing there’s someone waiting to take their job," Limegrover said. "And if they don’t put the work in, when they put their head on the pillow, someone’s going to catch them. There’s a lot of competition in there."