Peterson itching to play

How much does Adrian Peterson want the competition? The Vikings star running back was standing on the sideline during the early portion of Monday's practice watching the special teams when he looked over to the other field and saw the team's defensive ends and linebackers doing reps on a blocking sled.

"I said, 'You know what? Let me get active,' " said Peterson, who joined in the drill at Winter Park. "I was messing with those guys, saying I can definitely see myself coming off the edge. I don't know of too many tackles gonna get their hands on me. So keep your eyes out for it."

More seriously, keep your eyes out for Peterson actually seeing some action on offense Sunday night in San Francisco. It will be his preseason debut.

This after having lobbied coach Leslie Frazier hard to get in the first two exhibitions.

"When you sit back and watch two games and see your guys, that second game you start itching for it," Peterson said.

If he had the choice, Peterson said he'd like to play a half in San Francisco. But he likely won't play that much. Perhaps two series.

Last season, coming off knee surgery, Peterson didn't play at all in the preseason but won MVP honors. So he doesn't necessarily need the preseason reps.

First-round draft pick Sharrif Floyd might have played his last preseason down. Floyd underwent what Frazier described as a "minor procedure'' on his left knee.

"I don't think he'll practice until next week," Frazier said. "It's nothing major. He shouldn't miss any time, as far as our regular season is concerned. He won't play this week [at San Francisco] and probably not in the Tennessee game [next week].''

It was not an arthroscopic surgery, Frazier said, but a procedure to ease the pain at the front of the knee, which Floyd hurt in the preseason opener Aug. 9.

For the first time in a year, linebacker Desmond Bishop played in an NFL game, getting time with the backups against Buffalo on Friday night.

"It was fun," Bishop said. "But I didn't have the time to feel any emotion."

"You want to see if a guy can execute against good on good," Williams said. "I think that's one thing we'll try to do this week to make sure the guys we're looking at get good on good. Believe me, the 49ers have enough depth in their roster that we're going to get good on good with our first two groups.''

Bishop missed last season with the Green Bay Packers after tearing a hamstring in the preseason. The Vikings signed him after their offseason training work, then he missed time in training camp because of a groin injury.

• Veteran cornerback Jacob Lacey, whose attempt to make the roster was sidetracked by injuries, was released by the team. Lacey likely will receive an injury settlement.

• Left tackle Matt Kalil sat out a second consecutive practice because of a sore knee, but Frazier expects him back for Wednesday's workout. Also missing practice were wide receiver Jarius Wright (concussion), who is day to day; fullback Jerome Felton (appendectomy); and defensive tackle Christian Ballard, who is dealing with a personal matter. Long snapper Cullen Loeffler was back after missing Sunday's practice because of a sore elbow.