The Vikings have big issues to tackle this offseason, including the hiring of a new head coach. And the decision to keep or move on from Leslie Frazier will have a major say in the defensive direction of the team from there. Keep Frazier, and the Vikings can expect to remain a 4-3 "over" defense with cover-2 and Tampa-2 principles. Choose someone else, and all bets are off.
But even if Frazier stays, expect some changes on defense — perhaps significant ones on all three levels.
On the line, DE Ray Edwards is a free agent and might not return. He could outprice himself for the Vikings, seeking big money at a position where top pass rushers often get paid beyond their value. The Vikings have Brian Robison, who has been effective in limited snaps, and the emerging Everson Griffen, who could step up in Edwards' place. NT Pat Williams, although he says he wants to play beyond this season, might not be a part of the team's plans, which would open a hole inside.
Linebacker is probably the position that would undergo the fewest changes, but both SLB Chad Greenway and WLB Ben Leber are free agents. Greenway is expected to be a priority for the team, but Leber might not return.
The secondary almost certainly will see changes, and safety is the area of biggest need. FS Madieu Williams simply hasn't been the playmaker the team expected when he arrived from Cincinnati, and there is no other ideal replacement on the roster. Strong safety is far from an idea situation, either, with Hussain Abdullah a solid but hardly entrenched fixture. Right corner also has been a problem all year, and even with rookie Chris Cook likely to be in line for a starting spot, he could use some form of insurance. In addition, CB depth remains a concern.
The defense hardly has been the biggest issue this season, but it hasn't been the lockdown unit of the recent past, either. Whether or not Frazier returns, you can expect to see some changes on this side of the ball next season.