Vikings notes: Williams doubtful for season opener

Kevin Williams has missed only two games in 10 seasons because of injury, but his availability for Sunday's season opener looks in serious jeopardy.

The Vikings defensive tackle did not practice for a second consecutive day Thursday because a right knee injury. Vikings coach Leslie Frazier said Williams hopefully can do some work in Friday's practice, which likely will determine whether he plays against the Detroit Lions.

"He is making improvements, but [Friday] will be a big day to determine if we have a chance to get him ready for Sunday," Frazier said.

Williams suffered a hyperextended right knee, a significant bone contusion and a posterior capsular strain on a low block in the San Francisco preseason game. Frazier said he needs to see how Williams responds to contact before he would feel comfortable putting him on the field.

If Williams doesn't play, rookie Sharrif Floyd could get the start in his NFL debut. Floyd was bothered by a knee injury in preseason and has been limited in practice this week, but Frazier said that is no longer a major concern.

"He's done well," Frazier said. "He looks good. It doesn't look like there are any ill effects from his injury. Full speed ahead."

Frazier said Letroy Guion "possibly" could slide to Williams' tackle position from nose tackle for a few snaps. One other thing to consider: The Vikings often move defensive end Everson Griffen to tackle in their nickel defense. The Lions rely heavily on the passing game, which means the Vikings likely will use their nickel defense extensively so Griffen could see plenty of action at tackle, too.

Felton helped clear the way for Peterson's 2,097-yard season, but Peterson didn't sound overly concerned about how his primary fullback's absence might affect the running game.

"With Zach coming in, I think he's been around long enough to know how we do things, to kind of adapt to the offensive line and my running style as well," Peterson said. "So I try to stay in his ear. But we've got some other guys that we throw in there in different formations. We've got Rhett Ellison in there lead blocking at times. So we should be OK."

Peterson was asked what advice he's given Line as he prepares for his unexpected opportunity.

"I try to tell him to think like a running back," Peterson said. "Don't get too caught up in the X's and O's. Sometimes just go out there and play football. I think if you approach it that way, it'll be OK."

Jared Allen admitted it will be weird not seeing Jeff Backus lined up across from him Sunday. Backus played 191 career games and made 187 consecutive starts at left tackle for the Lions before retiring this offseason.

Allen's new matchup will be second-year tackle Riley Reiff. The Lions presumably will give Reiff plenty of help on Allen.

"I think I saw more chips and double [teams] last year than I've seen my entire life," Allen said.

Bobby Felder had a realistic shot to make the 53-man roster until he injured his ankle in the third quarter of the final preseason game. Instead, he ended up on injured reserve.

Felder, who suffered a high ankle sprain, will continue to do daily rehab at Winter Park. He pushed Marcus Sherels for the punt returner job and fifth cornerback spot in preseason.

"I think I had done enough to show them that I was worthy of being at least a candidate for a spot," Felder said. "Unfortunately, the injury had to come this late."