At this point in the NFL offseason, the vast majority of every team's roster building for the year has already happened. There are still some free agents out there and various moves to be made, but 90-man rosters are mostly pretty full with OTAs approaching. The Vikings, once they hire a new general manager, could still do some tinkering with their roster. They have one spot remaining under the 90-player limit. For the most part, though, the guys they've got are the guys they're going to move forward with. With that context in mind, let's take a look at the strengths and weaknesses of Minnesota's roster by ranking all of their position groups. We'll go from the room we believe is the Vikings' biggest strength to one that looks like their most significant current weakness. A few quick notes: Offensive linemen will be split up into tackles and interior players, specialists are included as one of the 12 rooms, and we made some judgment calls on players who can play multiple positions.…