Key free agents: QB Matt Cassel, DE Jared Allen, DT Kevin Williams, DE Everson Griffen, CB Chris Cook, WR Jerome Simpson

Where they stand: The Vikings' biggest issue is at quarterback, where Christian Ponder is the only player they have under contract. They've told Cassel's agent they want to bring him back, but that could depend on how much more interest Cassel attracts on the free-agent market. Of the free agents on the Vikings' defensive line, Griffen probably has the best chance of returning to Minnesota to play in Mike Zimmer's new-look defense. But he, too, could attract attention from teams who think he can be an outside linebacker in a 3-4 scheme.

What to expect: Cincinnati defensive end Michael Johnson could find a natural landing spot in Minnesota because of his familiarity with Zimmer and the Vikings' likely need for a new right end. Tennessee cornerback Alterraun Verner, who played for new Vikings defensive backs coach Jerry Gray in Tennessee, could also make sense for Minnesota, though both Verner and Johnson will have plenty of suitors. The Vikings have more than $40 million in cap space, though, so they could be contenders for both. If Cassel doesn't come back, the Vikings will also have to pursue another veteran quarterback; running back Adrian Peterson tweeted on Wednesday that Michael Vick could quickly turn the team into a playoff contender.