The official figures for the 2014 Franchise and Transition tags are out, and as you might expect, there are some pretty hefty numbers involved with using the tags. We won't get into the Transition tag too much, because it's basically worthless at this point, but the Franchise tag is still relevant. Here, then, are the numbers for each position from most expensive to least expensive.
Defensive End: $12,475,000
Wide Receiver: $11,539,000
Offensive Lineman: $11,126,000
Defensive Tackle: $9,182,000
Running Back: $9,074,000
Tight End: $6,709,000
When one takes a look at the members of the Vikings that are set to hit free agency in March, there really aren't any players that could be deemed worthy of the tag. As Ben Goessling points out, if the Vikings wanted to put the tag on their highest-profile free agent, defensive end Jared Allen, it would crush their cap situation. The Vikings have about $23 million in projected cap space as it stands right now, and as you can see above, using the tag on Allen (or even on Everson Griffen, which isn't happening) would eat up more than half of it.
It would be a huge upset if the Vikings were to use the franchise tag on any of their players this off-season, and one that wouldn't be prudent in any way for the team at the present time. There will be some interesting potential tags around the league, particularly in New Orleans, where the Saints are waiting to see whether Jimmy Graham will be counted as a tight end or a wide receiver for cap purposes. As you can see, the difference is pretty substantial. Minnesota, however, has no such intrigue.