MANKATO – A bullhorn erupted after each play during 11-on-11 periods at Friday's Vikings practice. It was the first time the loud, irksome noise had occurred during training camp, leaving many wondering what purpose it served.

Vikings coach Mike Zimmer intentionally had someone set off the siren five seconds after each play so the players would continue with the play after the initial contact was made. "I'm just trying to remind them that we have to go hard until at least this long each and every play," Zimmer said. "Some of the pass plays take a little longer. I'm trying to get them to understand that you do your job."

The horn typically goes off after five seconds because most plays don't last longer than that. Zimmer said he did this during his tenure as Bengals defensive coordinator the past six seasons to help set a level of expectation he has at practice.

"If you're standing over here and the ball is over there, we got to get our butt over there to help," he said. "Same thing with the offense. We can't block this guy and then stop. Let's keep blocking and stay on him. Basically, we want them to finish."

Even with the horn, Zimmer felt it was a sloppy practice that lacked precision from both sides of the ball. Quarterbacks Matt Cassel and Teddy Bridgewater threw interceptions during the 11-on-11 periods.

"We gave them a lot of different looks on defense today, too," Zimmer said. "That's part of the evaluation is it's not to line up there in the same look every time and they know where they're going before the ball is snapped."

Kicking from the new spot

Blair Walsh wrote a column for Fox Sports' website asking the NFL competition committee not to push extra-point attempts back to 43-yard tries but rather have 38-yard attempts.

While PATs will remain from the same distance as a 19-yard attempt, the NFL will experiment with 33-yard PATs during the first two weeks of the preseason. Walsh thought the distance was a good start for a more competitive extra point.

"I think you're still going to get a couple of timely misses if you had it all year," he said. "I just don't know if that's how people want the games to be decided. You already get enough grief from people that say games shouldn't be decided by kicker. I obviously disagree with that. So it just makes your kicker more and more important and more valuable."

Walsh was one of five kickers to miss an extra point last year. No one missed more than one attempt, while 30 kickers made all of their attempts.

Walsh has practiced from 33 yards since the NFL announced the change. He said that he's also practiced at TCF Bank Stadium, where the Vikings will play their first two preseason games, and that he hasn't missed an attempt yet from the new spot. "You can't always get attempts in a preseason game because you don't know how it's going to go," Walsh said. "Being in that stadium for the first time, those will be like short attempts for us."

A well-earned day off

Zimmer gave linebacker Chad Greenway and running back Adrian Peterson a day off Friday. Peterson was held out of Thursday's practice as well, while Greenway said it was the first training camp practice where he did not participate in his career. "Not many people get to this point in their career, so I'm blessed," said Greenway, entering his ninth season. "It was a lot of work to get here, and I'm proud of it, not looking down as a bad thing."