Mike Harris had spent the entire spring as the first-string right tackle before Vikings offensive line coach Jeff Davidson approached him with a surprising request at the end of June’s minicamp.

Harris was about to lose his starting spot to Phil Loadholt, the longtime Vikings right tackle who was at the time close to returning from a torn pectoral muscle. And he figured he would go back to being the team’s swing tackle, a role that led to him starting five games a season ago.

But Davidson told Harris the Vikings thought enough of him to pencil him in as a starter, albeit at guard, a position he hadn’t started at since Pop Warner football.

“I was excited. I just wanted to get out there,” Harris said, looking back. “It’s an honor and a privilege to start on an NFL team. I know there’s a lot of responsibility involved — preparation and watching film. But it’s my fourth year now. It’s time to be a pro and go out there and help this team win.”

So far, the 26-year-old has handled the responsibility at right guard well.

Harris has arguably been the team’s best offensive lineman in both of his first two NFL starts at guard. He was one of a few bright spots in the 20-3 loss to the San Francisco 49ers in the season opener. And he played well again in last week’s 26-16 victory over the Detroit Lions, whether he was keeping defensive tackles at bay in pass protection or creating running room for Adrian Peterson.

“It’s a work in progress, but I’m just continuing to get better each week,” Harris said.

The 6-7, 338-pound lineman had been an offensive tackle for most of his life before arriving in Minnesota last August. In a Week 7 loss to the Buffalo Bills, Harris was forced to play guard for the first time since he was 10 after center John Sullivan and right guard Vlad Ducasse both were knocked out of the game because of injuries.

That would turn out to be his only cameo at guard until this summer, when the Vikings, who didn’t like what they saw from a trio of youngsters at right guard, decided to give Harris a look at the position at the start of training camp. He seized the job.

Harris believes his experiences in both college and the NFL helped prepare him for the switch to the unfamiliar position. At UCLA, he switched between left tackle and right tackle depending on the offensive formation. And in 2012, offensive coordinator Norv Turner, then the coach of the San Diego Chargers, signed Harris as a rookie free agent and trusted him to be his swing tackle.

When he played tackle, Harris often was left alone on the outside to block defensive ends and pass-rushing outside linebackers. Now, he is dealing with defensive tackles who are heavier and stronger than edge rushers, though typically not as quick. The position switch also has challenged him mentally, because now he must think like a center when it comes to diagnosing complex blitzes.

Thankfully, Harris got plenty of practice in training camp by lining up across from a drastically different pair of defensive tackles in Sharrif Floyd and Linval Joseph and dealing with coach Mike Zimmer’s endless double A-gap blitzes.

“They were able to help me to improve my technique because we have guys that have speed and power, so I knew my technique had to be right,” Harris said. “And our defense likes to bring pressure, so that was able to help me start to recognize different blitz packages.”

Against the Lions, Harris allowed only a pair of quarterback hurries and has yet to be beaten for a sack this season, according to Pro Football Focus. Peterson, who rushed for 134 yards in the victory, had success running behind Harris.

“He was able to adapt real quick,” rookie right tackle T.J. Clemmings said. “And he’s been doing a great job so far.

With Clemmings trying to keep his head above water after the latest season-ending injury to Loadholt, Sullivan out at least the first two months of the season after back surgery and left guard Brandon Fusco missing Wednesday’s practice due to a concussion, the Vikings need Harris to continue to be a stabilizing force against his former team this weekend.

“We’re starting to jell much more,” Harris said. “We just need to continue to grow from that game.”