One of the most frequently-asked questions about plans for the Minnesota Vikings new $975 million stadium is whether it will have a fixed roof or a retractable roof. 

The stadium legislation signed by Governor Mark Dayton provides for a fixed roof. Moreover, it specifically states that if the Vikings owners want the fancier, retractable model they're going to have to open up their big, fat wallets a little wider and pay for it themselves.
You know the Wilfs are thinking about it. In fact, they've said they're going to try to make it happen.
Among the reasons for a retractable roof: soccer.
A provision in the stadium deal gives the Wilfs a window after the new place opens to lure a Major League Soccer franchise to play in the new digs. Zygi and Mark Wilf have already been in touch with MLS officials about doing just that. Soccer would need to be played "outside," as in "with the roof open."
Something tells me they'll get it done. To the Wilfs, building the new stadium without a retractable roof would probably be tantamount to driving the ball down to the one yard line and settling for a field goal attempt instead of a touchdown. And then kicking it wide right.
It's not entirely clear how much a retractable roof would raise the price. I've heard estimates in the $20-50-million range, but who knows? Converting a stadium with no roof to a retractable roof could cost more than $100 million and ripping off an existing fixed roof and replacing it with a retractable version costs several hundred million bucks. If the retractable version is part of the original blueprint, the cost is dramatically less.
Assuming the retractable roof plans are ultimately green-lighted by the Wilfs, the question of when to have the roof open and when to close it would come into play. Zygi has already joked about opening it up for snowstorms. At least I think he was joking. The NFL doesn't have published rules that stipulate opening or closing a roof based on weather conditions, but other facilities with retractable roofs -- such as the ones in Indianapolis and Houston -- have their own set of weather-related guidelines.
If the Vikings pay for a retractable roof, my best guess is that the roof would remain open for Vikings games until sometime in October. Once the mercury starts dipping below 40 degrees they'll probably shut it.
Vikings quarterback Christian Ponder, who should be in the prime of his career when the new stadium opens, sees pros and cons to having a retractable roof. "I love being outside, but playing in late December, I think that's going to be tough," he told me Thursday at Winter Park. "At the same time it could be a home field advantage for us."
I was meeting with Ponder for a piece I'm writing for the Vikings 2012 Yearbook, but I couldn't resist getting his take on the new stadium even though the roof decision will likely be made before the Yearbook goes on sale at the Metrodome.  
"I think a retractable roof is kind of pointless," Ponder told me, referring to how they've been under-used elsewhere. "You see all these teams that have a retractable roof that don't really use it. Obviously the idea is great… but I feel like a lot of [teams] don't use the 'retract ability' at all."
The young quarterback makes a good point. If the Wilfs do decide to spring for the extra amenity, they better use it. It might be a mistake to leave the roof open in December as Zygi hinted they'd do, unless of course we keep having winters like the one we had this past year. But prematurely closing it for games in September would be just as silly. Ultimately, it would be nice to have at least some outdoor Vikings football back beyond just the season or two they'll be playing at TCF Bank Stadium.
After decades of Metrodome football, you can officially count me in as being in favor of the retractable roof. Then again, I won't be the one paying for it.
Bo Mitchell is the Vice President of Content at SportsData and co-host of the Fantasy Football Weekly radio show on KFAN 100.3 FM.
You can follow Bo on Twitter at @Bo_Mitchell