Minnesota Vikings K Blair Walsh warmed up alongside 49ers K David Akers on opposite hash marks in windy Candlestick Park on Friday, and as they moved back to kick from a farther distance, each appeared to be trying to outkick the other. Akers, who is 37 years old, attempted a kick from the 55-yard line that barely made it into the end zone, and then Walsh followed by kicking from 63 yards and hitting the upright. Special-teams coach Mike Priefer said he enjoys that sort of friendly contest.

“I love that competition because I was in the AFC West with (Raiders punter) Shane Lechler and (Raiders kicker) Sebastian Janikowski, and they did it every time we’d played them,” said Priefer. “They’d go out there and show off. Of course, I had Matt Prater in Denver, who pretty much matched Janikowski.

“This young man (Walsh) has a big-time leg, and I think the more confident he gets and the more success he has the better kicker he’ll be for us in the long run.”

Smith takes first-string reps: As coach Leslie Frazier indicated (on Sunday) might happen, FS Harrison Smith took first-string reps in front of Jamarca Sanford at Monday’s practice. But Frazier was quick to point out that no decision had been made on starting positions.

“We want to see how he does,” said Frazier. “It’s not a permanent deal. We still have to make a decision: Can he handle that? And this will be a good test for him, because Buffalo, I don’t know how much they’ll play their starters, but they've got a pretty good passing offense. So we’ll see.”

No Josh-ing, Robinson is back: CB Josh Robinson got back on the practice field Monday, and he looked good after missing Friday’s preseason game with an injured hamstring. He hurt it early in camp, tried to make a comeback and was derailed when he tweaked it.

At Monday’s practice, Robinson nearly intercepted one long pass and chased WR Percy Harvin on another play, hanging with him the whole way while a coach was overheard saying, “Watch your hamstring!”

“We are [excited to have] him coming back,” said DC Alan Williams. “He was doing some very good things before he went out. I’m excited about him being back and on the field and seeing him take that next step.”

Injury update: LT Matt Kalil left the middle of practice apparently dealing with some pain in his thumb, but he later returned to practice and took part.

“Kalil is fine,” said Frazier. “He actually bumped his thumb. They did an MRI. Everything was fine. He came back, finished practice. So that was encouraging.”

OL DeMarcus Love returned to padded practice for the first time in a couple weeks, worked through some of the drills and then left practice to remove his pads. He did no team activities, and Frazier said it would be another week before he returns to full practice due to his shoulder injury.

DE Jeff Charleston, who recently returned from an ankle sprain, was sitting out practice on Monday afternoon with what might be a concussion.

“He was complaining a little bit about headaches after the game the other night, so we had to run some concussion tests just to make sure everything was fine,” said Frazier.

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