Vikings coach Mike Zimmer didn't appear ruffled in the least when asked to respond to accusations from Lions receiver Golden Tate that the Vikings are a dirty team that took cheap shots in Sunday's game at TCF Bank Stadium.

"That doesn't bother me," Zimmer said. "I know what kind of team we are. We're not dirty."

Zimmer then apologized to linebacker Anthony Barr. On Monday, Zimmer called Barr's personal foul penalty — pushing quarterback Matthew Stafford as he was running out of bounds late in the game — a "dumb penalty."

"I probably owe Anthony Barr an apology because I talked to the [league] officials [Tuesday] night," Zimmer said. "These quarterbacks now, they're starting to slow down as they go out of bounds. Kind of egging these things on. That's one of the things we talked about and [the official] said, yeah, [Barr's penalty] probably should not have been called."

Zimmer said he called the league office for another matter and ended up talking to an official about Barr's penalty.

"I saw in a couple of other games where these [quarterbacks] were going out and they step out late or … he was running parallel, kind of slowing down," Zimmer said. "What [the league official] told me was they do not get protection if they slow down. [Quarterbacks] need to try and get out of bounds."

On a broader point about accusations that the team is dirty — a point that wasn't expressed by Lions coach Jim Caldwell, by the way — Zimmer said:

"We try to coach within the rules. We try to do things the right way. We want to be a football team that's known for teaching proper technique. We're not trying to cheat the rules and I don't want our football team to be put at a disadvantage because other people are trying to cheat the rules. I want our guys to know the rules, play by the rules and play fair."

Other highlights from Zimmer:

— On kicker Blair Walsh's slump and whether there have been issues with the holds and the snaps: "No. I think the holds have been good. I think the snaps have been good. He just has to continue to do it in the games. He's been good in practice."

— On whether there is anything that changes with Walsh's technique in games: "No. I don't think so. Sometimes, they may get a little sped up. That might be a little bit of it. Just the rhythmic thing of it. It's like the golfers."

— On whether the new 33-yard PATs are more stressful on kickers or coaches: "I guess probably both a little bit. I think the conversion rate is like 94 now on the extra point. The two-point is 53 percent, so it's still a little bit iffy on that. I think you might have a little bit of tendency to try to even it up later in the ballgames. But I think the kickers will get adjusted to it as we continue to go throughout the season. I think they'll continue to get better at it. Extra points, they used to think was automatic, where now they have to put a little bit more concentration into it, I would guess."