MANKATO – With Stephen Burton making plays, turning heads and moving into early position as the fifth receiver on the Vikings roster, coach Leslie Frazier was asked if any weight will be given to receiver Joe Webb's versatility and past as a quarterback when it comes time to make the final cuts at receiver.

Frazier's answer makes it clear Webb shouldn't bank on anything but what he shows as a receiver.

"He's mainly evaluated as a receiver, and we'll see how he comes along," Frazier said Sunday as the Vikings returned to practice at Minnesota State Mankato. "He had a couple nice catches on Friday night. We've just got to keep putting him out there and giving him opportunities both here at practice and in games, but he's been evaluated as a wide receiver."

Webb has shown solid hands but understandably raw route running in camp. He had two catches for 11 yards in Friday night's 27-13 preseason opening loss to Houston at Mall of America Field.

Burton, meanwhile, has been one of the top surprises in camp. He continued a solid summer with three catches for 67 yards on Friday. His night included a 56-yarder in which he alertly planted and reversed field to surprise a defender.

The Vikings' top four receivers are set: Greg Jennings, Jerome Simpson, Jarius Wright and rookie Cordarrelle Patterson. The Vikings probably will keep five or six, but Frazier made it sound like keeping only four might not be out of the question.

"We're undecided [on keeping five or six]," Frazier said. "You know it's so early now, we need to get some more games, some more stats, and see if there's anyone deserving of being the fifth wide receiver or sixth wide receiver on our roster. I think it's too early to say that that guy is here. We have some more work to do before we can determine that."

Floyd's knee fine

Rookie defensive tackle Sharrif Floyd said his knee was fine, and now he has the negative magnetic resonance imaging exam to prove it.

"Everything is fine," said Floyd, who sat out practice Sunday. "It was nothing to be scared about. If I had to go back in, I could have gone back in."

Floyd said he was injured when he was cut from behind in the first half Friday. Before leaving the game, Floyd had a pass deflection and a tackle for loss in an active night.

"The first experience went well," Floyd said. "Now I just want to get back as quick as possible and find out what I can do better."

Meanwhile, rookie cornerback Xavier Rhodes (hamstring) and linebacker Desmond Bishop (groin) returned to practice after missing a week of workouts and Friday's preseason game. Cornerback A.J. Jefferson (hamstring) also returned to practice, while linebacker Audie Cole was held out.

Lacey out 2-4 weeks

In all likelihood, Jacob Lacey's chances of making the final roster ended Sunday when Frazier announced that the veteran cornerback will undergo arthroscopic knee surgery and miss two to four weeks. Lacey, who didn't play Friday, was signed off the street this offseason. He spent time with the Lions and Colts and was brought in as insurance in case second-year pro Josh Robinson couldn't make the transition to the nickel slot corner position that came open when Antoine Winfield was released.

More work for starters

Those hoping for more than two plays from the first-team offense will get their wish Friday in Buffalo. Frazier said starters on both sides of the ball will play into the second quarter. Frazier did a nice sidestep when asked whether that includes running back Adrian Peterson, who along with several other star players didn't suit up Friday.

"He's always in the conversation," Frazier said. "We'll see where it goes with him. But he's always in the conversation when we talk about our offense."

Etc.

• Backup center Joe Berger, who missed time the past week because of a death in the family, returned to practice Sunday.