Sean Ferguson figured he could take it slow, spend the spring tinkering with technique and absorbing assignments as he learns his new position. Next thing he knew, he was playing with the first team at right tackle, and being held to the same high standards as three-year starters.

"It's like they threw me in there to sink or swim," Ferguson said. Wait, isn't that a weird analogy, considering how few 315-pound swimmers you see in the water?

"Well, we float pretty well," he agreed.

He's done more than that, though. The 20-year-old redshirt freshman has been filing in for injured starter Jimmy Gjere. Ferguson has survived this month's Camp Kill-In-Your-Face, and even thrived despite shifting from defense to offense, studying under a whole new staff, and persevering under the demanding do-it-again tutelage of Jerry Kill. There have been days when Kill seemed more ogre than tutor, tucking himself under the 6-6 Ferguson's face mask to loudly criticize his blocking and extract extra work as penalty.

"It's not that he's picking on me. They see my potential and they want me to fulfill it. The extra running, although it may seem like punishment, I'm getting better from that. [Kill] is trying to make me better," Ferguson said confidently. He paused a second, then added: "It's just excruciating, that's all."

Small price to pay if it means playing football, he said. Ferguson played both offensive and defensive tackle at a prep school in Philadelphia before signing with the Gophers 15 months ago, and was initially told he would anchor the defensive line here. But after Kill arrived in December, he watched film of Ferguson practicing, and approached offensive coordinator Matt Limegrover with an opinion: The kid's a natural blocker, not a run-stopper.

He wasn't the first coach to come to that conclusion, either. At a high school game in Philadelphia, the grandfather of an opponent approached Ferguson, then playing defense, to tell him he looked like he had the talent to be a great offensive lineman.

Coming from Dick Vermeil, who coached the Eagles and Rams into the Super Bowl, those words stuck with him.

So when Limegrover and Kill pulled him aside this winter and proposed the switch, they were shocked by Ferguson's enthusiasm.

"He's the first kid I've ever been around who wants to be on O-line. As soon as I said that's what we want to do, he goes, 'Woo-hoo!'" Limegrover said. "Usually, they fight and kick -- it's like Last Chance, USA. But he was fired up because he's smart enough to realize, 'I can be a bad athlete among the D-linemen, or I can get out there and make the most of this.'"

The transition hasn't always been smooth -- whereas defensive linemen are trained to simply be aggressive, offensive linemen must be more cerebral about executing the plays. Ferguson said he's still thinking too much before acting -- but he is one of the most improved players on the team this spring.

"I'm proud of him. He's gotten a lot better," Kill said. "Someday, he'll be a good offensive lineman when he learns what to do."

• Senior receiver Da'Jon McKnight (knee) and tight end Eric Lair (concussion) won't take part in the final week of spring practice, Kill said. Both will be 100 percent by fall camp, Kill said.