It has appeared for most of the offseason, ever since the Vikings drafted Sharrif Floyd, that they would be dealing from a position of strength in the middle of their defensive line. The Vikings planned to rotate Floyd and Kevin Williams at their three-technique tackle spot, and pair Letroy Guion with Fred Evans at the nose. They would be able to rotate four players, possibly mixing in Christian Ballard, and hand one of the inside spots to Everson Griffen on third downs to rush the passer from the inside.

That plan sounded nice in theory, but the details have been muddied by reality. Williams didn't practice on Monday, as the Vikings began their preparations for their season opener with the Detroit Lions. Floyd, who was back on the practice field, hasn't played since the Vikings' second preseason game, and could be thrust into a starting role in his first NFL game. Ballard is on the team's reserve/left squad list. Guion could wind up going back to the three-technique position, rotating with Floyd there and Evans at the nose if Williams can't play. Chase Baker, who hasn't played a NFL game, is the only other defensive tackle on the roster.

It's another reminder of how quickly the best-laid plans can get altered in the NFL, and as the Vikings head into Week 1 against Detroit, they suddenly have a reason to be concerned about what looked like a position of strength.

Frazier didn't offer much detail about injuries on Monday, probably because the Vikings aren't required to file an injury report until Wednesday, but the fact that Williams didn't practice probably means things aren't looking good for the Lions game. Williams is trying to come back from a hyperextended knee in two weeks' time, and rushing him back isn't in the Vikings' best interests.

But can Floyd handle a bigger role in his first game, after not having practiced in two weeks? That remains to be seen.

"I think we’ll have to go through this week and determine that, but he’s missed quite a bit of time and then (he's) coming off an injury," head coach Leslie Frazier said. "We’ll have to gauge that as the week goes on.”

Guion played the three-technique spot before shifting to nose tackle full-time last season, and the fact that he's not a typical wide-bodied nose tackle -- which might hurt him at his normal position -- could actually work in his favor here. But the Vikings are probably at their best at the nose when they have both Guion and Evans fresh, and they could be stretching their depth on Sunday if Floyd needs help on his side.

There might not be any perfect options for the Vikings in Week 1. There rarely are in the NFL. But it's striking to look at how quickly the defensive tackle position has become a worrisome spot for them.