A historically terrible Vikings season took a turn for the worse on Monday when it was learned Adrian Peterson has a high left ankle sprain. Granted, it's a Grade 1 high ankle sprain, which is the least severe of the high ankle sprain family, but it's a significant injury nonetheless for someone who relies so much on his feet.

High ankle sprains are particularly tough on skill position players who run and cut for a living. I'm not a doctor, nor have I examined Peterson's ankle or spoken with those who have. However, based on countless examples over the past decade, the typical timetable for the return of a running back with a high ankle sprain is anywhere from four to six weeks. Of course, four-to-six weeks puts us in the neighborhood of Week 15, 16, or 17. Translation: this has the potential to be a season-ending injury.

Do I think it will be season-ending? No.

Do I think it should be? Maybe.

A recent injury comparison can be made to Cowboys running back Felix Jones, who suffered a high ankle sprain in Week 6 against the Patriots. He missed their next four games and was brought back this past Sunday in a part-time role. His ankle is still not 100 percent, and probably won't be the rest of the season.

(Side note: Jones was Wally Pipped out of his starting gig by rookie DeMarco Murray while he was out. I'll boldly predict Toby Gerhart won't do the same to Peterson while he's rehabbing his bum wheel. )

As tough as he is, Peterson has no shot of playing on Sunday against the Atlanta Falcons. The Vikings don't need to release their official injury report until Friday, but Peterson is in a protective boot right now, won't be practicing this week, and will be listed as questionable, doubtful, or out. My best guess: out.

It's tough to pinpoint just how long Peterson will remain sidelined, but if I had any say in the matter I would error on the side of extreme caution. I'd even consider letting him spend the rest of the season in street clothes.

Peterson is a fast healer and the sprain is a mild one, so it could be reasonably argued that the typical four-to-six week timetable doesn't really apply in this situation.

You can bet there will be talk immediately following next Sunday's game of Peterson potentially returning to action for their Week 13 home contest against the Denver Broncos. Right now that game reportedly has more than 5,000 tickets remaining, which puts the Vikings' sell-out streak in real jeopardy – especially if Peterson isn't going to play. I'm not suggesting by any means that the Vikings would rush Peterson back early to avoid the blackout on local television, but I can already hear the cynical media speculation along those lines.

You know Peterson will be begging the coaches to return as soon as he can walk without limping or without letting on that he's still hurting.

The question is: why let him?

Why let your franchise's most important player -- whom you just signed to a seven-year, $96-million extension a few months ago – come back too early from an ankle injury?