The Vikings' rain-shortened practice couldn’t dampen the enthusiasm of RB Adrian Peterson on Sunday afternoon, when he donned a helmet and returned to practice for the first time since injuring his knee last December.

Peterson was taken off the active/PUP list on Sunday morning and he was all smiles in the afternoon, talking about finally reaching this hurdle in the rehabilitation of a torn ACL and MCL in his left knee.

“I was like a kid in the candy store today when they threw me out with the first group,” said Peterson. “I was just smiling. I had to kind of calm myself down. I was going a little too fast for a walk through in the beginning. This is just satisfying to me. A lot of people doubted me, but I kept my faith and kept working hard. Now I am back in the mix.”

Peterson cannot hit in practice until Tuesday, but it was enough for him to walk through plays inside the field house at Minnesota State University—Mankato to get his juices flowing.

“It’s the next step. I feel good to be off the PUP,” said Peterson. “It’s good that I am back out here with the guys on the field.”

It’s been over seven months since Peterson’s surgery. The next step hitting in practice and perhaps see some live action in a preseason game.

“Hopefully, I can get some snaps in the preseason,” said Peterson. “If not, oh well. I feel like I will be ready to roll either way. I am just going to see what call they make.”

Clean play pleases Frazier: Coach Leslie Frazier was pleased with his team’s lack of penalties on Friday night against San Francisco. Although he didn’t appreciate the special teams penalty, he was happy there were only two others (one on offense and one on defense).

No grades for officials: When asked about the replacement referees effect on the game, Frazier kindly deferred and said, he couldn’t talk about the replacement refs. “The officials did the best job they could do in that game. Next question.”

Smith could start against the Bills: Frazier on the play of rookie S Harrison Smith: “We felt Harrison was really making a push, he’s going to get a chance to work in that first group. He’s done enough now where we feel confident that he can go out there in a starter’s role and we want to see how he performs in that role. He very well could start Friday.”

Latest on Letroy: DT Letroy Guion left Friday’s game against San Francisco with a strained PCL injury, but Frazier feels he will be back in time to possibly play in the third preseason game.

“You don’t really want him to miss a whole lot of time because he’s a guy that we are counting on to really be a factor for us at that position, a major factor,” Frazier said. “Extended time loss would be a negative for what we are trying to do. Fortunately for us, based on what we are told, it is only going to be a one to two week injury. We should get him back for the third preseason game, which will be fantastic.”

Plugging the holes: The Vikings defense gave up 198 yards rushing in the first half on Friday, and coach Frazier said there were a lot of mistakes made on the field. But he hopes to clean them up this week.

“I think they are correctable. We’ll be playing Kevin Williams and Jared Allen and some of those guys the rest of the way," Frazier said. "Getting Jasper Brinkley back into the swing of things, that’s a process. Unfortunately we won’t have Letroy (Guion) to get more reps, but Fred Evans and Christian Ballard--getting those guys more opportunities should help us to do a little bit better job in run situations.”

For more news and notes on the Vikings follow Joe Oberle on Twitter @CBSSportsNFLMIN.