MANKATO -- Touching Adrian Peterson will remain a big practice no-no until at least next week.

"At some point here real soon, maybe next week, we'll let him get a little contact," Vikings coach Leslie Frazier said after this morning's walk-through. "It depends a little bit on how he's feeling and where he is. We want to get him a few more reps today and increase that as we go along."

Peterson was in full pads for the first time on Tuesday. He got 10 snaps and two carries, but defenders were told and reminded often to keep their hands off the face of the franchise and the left knee that was surgically rebuilt just 7 1/2 months ago.

Peterson will practice again this afternoon, but will not play in Friday night's preseason game against Buffalo at Mall of America Field.

Meanwhile, Frazier said the healthy scratches from last week's opener -- Percy Harvin, Kevin Williams, Jared Allen and Antoine Winfield -- will play against the Bills.

"Our goal is to try to get [the starters] at least through the first quarter and maybe part of the second quarter as well," Frazier said. "We have a number of plays we want to get to."

Sullivan emerging as team leader: Frazier singled out center John Sullivan as a player who emerged as a team leader during the Vikings' three-week stay in Mankato. That makes sense since Sullivan went from being the team's second-youngest offensive line starter last year to its second-oldest offensive line starter this year.

"There are a couple of guys that I'm really impressed with, one being John Sullivan," Frazier said. "I really like the way he's stepped up. I don't want to put a bright light on him. He's kind of been in the shadows of some of the veteran players who lined up with him in the past. All of a sudden he finds himself in a leadership role. He's really beginning to take that, and we need that. [Right tackle] Phil Loadholt has been another guy doing the same thing. We have other guys stepping up on the other side of the ball, but John is the one who kind of sticks out to me."

 Identity emerging as camp breaks: The Vikings break the Mankato portion of training camp after today's practice. Earlier today, Frazier talked about the identity he believes is emerging on the team.

"We feel like it's been a successful training camp," Frazier said. "A lot of the things we set out to do are being accomplished.

"We have some goals for what we want our offense, defense and special teams to look like. I think one of the things that came out of this training camp is we are coming together as a team. We're taking on the characteristics we like to have as a team. We want be a tough team. We want to be a smart team. We want to be a disciplined football team. We're seeing that in the way we're practicing. I saw some of it in the San Francisco game. Now, it's a matter of are we talented enough to go out and do the things we have to do on Sunday. But I think the foundation is being laid to do it the right way. The rest of it has to come over time."

Bethel-Thompson still competing for No. 3: The Vikings most likely will keep 33-year-old Sage Rosenfels as their No. 3 quarterback since they gave him a two-year, $3 million deal with some guaranteed money. He's also a favorite of General Manager Rick Spielman. But 24-year-old McLeod Bethel-Thompson is turning heads with what might be the strongest arm in camp.

Frazier was asked if Bethel-Thompson's best-case scenario is making the team's practice squad behind Christian Ponder, Joe Webb and Rosenfels.

"Right now, as we speak, he's fighting for that third spot," Frazier said. "Things could change, but he's fighting to get that third quarterback. We're not pigeonholing him and saying he has to be a practice squad candidate.

"We like having Sage. That was one of the reasons we signed him back, his veteran experience. We'll see how that all shakes out. But there is competition across the board, even at the quarterback position with the third spot."