The Vikings are in the enviable position of having four cornerbacks that they'd be comfortable starting. OK, maybe they wouldn't feel real comfortable starting Trae Waynes, but he's a rookie first-round draft pick who gets closer to starting every day and will be a starter at some point before next year's opener.

Today, coach Mike Zimmer announced that another corner is being added to the mix in practice today. Josh Robinson, who started five games a year ago and also served as the nickel back, will return to practice today. He can remain on PUP for three weeks before the team has to make a roster move.

"It will be good to get him out here," Zimmer said.

So what is he expecting to get from Robinson this season?

"He comes to all the meetings and pays attention and all that stuff," Zimmer said. "I don't know. We'll just have to see. It's different when you're watching it and you're covering somebody. That will be a little different."

Meanwhile, the mystery of Everson Griffen's illness continues for another day. Griffen was a surprise game-day inactive on Sunday. Zimmer said Griffen became ill Sunday morning but was expected to be fine and return to practice this week.

But that return probably won't come until Thursday, Zimmer said today.

"He's finishing up some tests today," Zimmer said. "We're anticipating that he'll finish good. I don't know that he'll be at practice today."

Here are some other highlights from Zimmer's press conference today:

— On Shamar Stephen, who was placed on injured reserve on Tuesday: Asked if Stephen broke his foot, Zimmer said, "I guess." Asked if he could have come back this season if he hadn't been placed on season-ending injured reserve, Zimmer said, "Iit would have been a long time. Eight weeks probably."

— On cornerback Xavier Rhodes picking up his eighth accepted penalty of the season, a holding call in Sunday's game against the Chiefs: "What happened on the penalty last week is he thought it was a run. The tight end came out and kind of hit him and threw him down and he thought it was a run. He's been working real hard at [avoiding penalties]. He talked to me again this week about some of the things he needs to work on. He's conscious of it. And there is point where … I don't want penalties, obviously, but I do think aggressive penalties are better than non-aggressive penalties."

— On defensive end Brian Robison's improved play this season: "Brian works really hard and I think in the offseason we sat down and talked about a lot of things. And [defensive line coach] Andre [Patterson] showed him a lot more things. I think as you get more comfortable with the scheme, now you can work on the intricacy part of the game. I think even though he's a veteran guy he's learning things now and understanding the way we're trying to do things."

— On defensive tackle Kenrick Ellis, a five-year vetearan who was signed to replace Stephen: "Big, strong, similar to Shamar. More of a run defender. He's been with a couple different schemes. I think his scheme and our scheme will fit for what we want him to do."