EDEN PRAIRIE, Minn. — The competitive fire inside Adrian Peterson has burned for more than a year.

After the Vikings wait longer than all but one other team to open the 2015 regular season on Monday Night Football at the 49ers, the running back will try to control release of the flames one carry, catch or assist with a pass block at a time.

"I'm pretty fired up, mostly just focusing on my assignment and the preparation leading up to the game, so I'm still doing a good job of keeping everything inside," Peterson said Friday.

The franchise leader in rushing yards and 2012 NFL MVP, however, will take the field for the first time since the 2014 season opener.

"I'm looking forward to it. That's kind of what I've been saying, just trying to keep it inside and not get too excited," Peterson said. "It's hard, but I know from the past when I go into a game and I'm too wired up, you forget about your principles when you're out there being slow, and then things develop. When that first snap comes, whenever it is, first play, second, third play, second series, I don't know. I'll take a deep breath and be ready to roll."

The dose of oxygen may help, but Peterson's desire to do well for the Vikings and himself will be the firewood.

The Vikings have had numerous changes since Peterson last took the field. A total of 18 players on the 53-man roster are different from the roster the Vikings had on Sept. 10, 2014.

Matt Kalil at left tackle is the only player on the offensive line in the same spot as a year ago. The Vikings have moved Brandon Fusco to left guard, plugged in Mike Harris at Fusco's former spot and are likely to start Joe Berger at center and T.J. Clemmings at right tackle in place of injured veterans John Sullivan and Phil Loadholt. The Vikings also have a quarterback, second-year pro Teddy Bridgewater, who hasn't played in a game with Peterson.

That doesn't mean Peterson, who was voted as one of four **captains** by teammates, hasn't made an impression on the 2014 Pepsi NFL Rookie of the Year.

"Oh man, you can just feel his presence from the moment he walks into this facility that he's ready to play," Bridgewater said. "He's had an entire year off and we're excited for him. We can't wait to watch him running wild on Monday.

"He comes to work every day and he's eager to be great," Bridgewater said. "With Adrian Peterson, we're not just talking about any running back, we're talking about a future Hall of Fame running back, so to bring him back into this offense and to watch him play, it's going to be exciting."

Peterson saw from afar a defense that improved considerably last season in its first under Head Coach Mike Zimmer from 2013 results.

"Personally I feel like we collectively offensively and defensively have a lot of talent, a lot of young guys as well, but some young guys that can really play ball, so I've gotta give Rick Spielman a pat on the back for drafting good talent."

Zimmer, not much of one for hyperbole, said of Peterson's return, "I don't think he is going at it nonchalantly."

The 49ers also have changed considerably, with a likely seven new starters on defense, but Peterson is expecting fierce foes.

"One thing I know about their defense is they fly around to the ball," Peterson said. "It's a physical defense, which I love."

First tandem test: The 49ers supplemented Anquan Boldin this offseason by bringing in speedster Torrey Smith, and the duo will be the first prolonged test for the Vikings pass defense of a 2015 season filled with multiple threats.

Defensive Coordinator George Edwards said he feels good about the prep work the Vikings have had in training camp from their teammates. Asked if Mike Wallace can help prepare for a receiver like Smith, Edwards said, "there is no doubt about it."

"Our receivers – they're a competitive group, they do a good job of coming to work every day," Edwards said. "Mike and the rest of the receiving group has really helped us; you can tell. We have to go out there and compete every day against that caliber of talent."

Flash back: Cordarrelle Patterson started at receiver but didn't return any kicks in the final preseason game, but Special Teams Coordinator Mike Priefer said the 107-yard touchdown against Dallas the previous week gave the whole return team a confidence boost.

"I think the Dallas return really helped him, I think it helped our whole group," Priefer said. "We had one quality return earlier in preseason, but Marcus [Sherels] returned it. Cordarrelle finally got an opportunity to return a ball and he did a great job with it. Did exactly what we asked him to do, it was a well-blocked play. We're hoping that that's kind of a precursor of things to come for our kickoff return team this season."

Patterson, nicknamed "Flash," led the NFL and set a Vikings record by averaging 32.4 yards on kickoffs during his 2013 rookie season. Last season, he averaged 25.6.

Quote of the day: "I'm pretty good at finding the head coach when he wants to tell me something."

— Priefer on choosing not to wear a headset during games