Brandon Fusco felt as if he was writing with the wrong hand last season.

And on top of switching from from his usual spot at right guard to left guard, Fusco said his hands only had half their normal strength.

The worst of Fusco’s three full NFL seasons as a starter for the Vikings was preceded by his first major surgery, to repair a torn right chest muscle. That rehab process left him behind in the weight room, Fusco said, entering a season that would be his first — and last — at left guard.

“The pec injury is not very fun to come back from,” the 310-pound Fusco said. “It’s a very big injury for an offensive lineman. All my upper-body strength wasn’t the same. Felt like my whole offseason was just rehab and just trying to get to a point where I was able to play. So, I wasn’t really strength training and what I was used to.”

Now that he has moved back to the right side, Fusco has much to prove two years into a five-year, $25 million extension signed only 18 days before he tore his pectoral muscle.

Another injury, this one to a shoulder, briefly interrupted what coach Mike Zimmer called a “good camp” for Fusco. He returned to practice last week and expects to reintroduce himself at right guard Sunday in his preseason debut — with aim to deliver more force than a season ago.

“I was doing 50-, 60-pound dumbbells in last year’s rehab,” Fusco said. “I’m now well over 100, 150s, so my strength is a lot better. … It’s like I doubled my strength since my rehab. I feel like I’m in really good shape and feel good out here.”

Despite boasting the league’s leading rusher in Adrian Peterson, Vikings blockers left many yards on the field for him. Fusco was not the only blocker to stumble in trying to clear a path or protecting quarterback Teddy Bridgewater. He and rookie tackle T.J. Clemmings tied for the team lead last season with 42 quarterback hurries allowed, according to Pro Football Focus.

In part because of Fusco’s play on the left side, a switch that he attributed to some of his issues, the Vikings made Alex Boone a priority free agent. Boone signed a four-year deal with $10 million guaranteed to start at left guard, allowing Fusco to move “back home” on the right side.

First-year offensive line coach Tony Sparano is another change in Fusco’s rebound bid. Sparano has been credited with bringing an aggressive mentality and changes to technique, though he has also implemented new running schemes with an emphasis on attacking outside, Fusco said — not unlike how he used to pull around Phil Loadholt to spring Peterson for big gains on the right side.

“He’s back at right guard, and I think what we’re doing in the run fits him,” offensive coordinator Norv Turner said. “So we expect him to have, really, a good year.”

Less than two years after he was a sixth-round pick, Fusco earned the right guard job in 2012. He was part of the crew that helped spark Peterson’s 2,097-yard season. Another strong year from Fusco led to the contract extension that includes pay raises for Pro Bowl appearances. That’s where his career was headed.

However, an unstable 20 games for this coaching staff, including 17 at left guard, have left uneven impressions. Fusco, 27, is entering his own prove-it season as most NFL contracts, like his, become expendable after the initial couple of years.

“He’s a tough guy, so I think I have a good idea,” Zimmer said when asked if he fully knows Fusco’s abilities. “There’s a couple things you kind of wonder about still a little bit, so you’re trying to see those.”

With last year’s right guard, Mike Harris, sidelined by an undisclosed illness since June, Fusco has transitioned back into his old spot without competition.

Though he is still playing to secure his future.

“I feel like now I’m back to the player I was,” Fusco said. “Just have to prove to all the coaches, teammates and fans who are watching.”