If the Vikings didn't think Kirk was worth $100 million in cash guaranteed, them not resigning* him isn't shocking.
Unless the Vikings have a trade lined up for a spot that will get them a QB, however, them spending money like they aren't the third best team in the division doesn't make much sense.
Speaking of not much sense, the Falcons are giving Kirk $100+ million after a year with Russell Wilson and Aaron Rodgers (and Kirk's own injury, for that matter). I get that the Buccaneers hardly have a stranglehold on the NFC South, but I'm not sure I like the odds on that play.
*Wasn't a release, Kirk is no longer under contract as of Wednesday.