When the Vikings chose to exercise their prerogative to keep quarterbacks coach Kevin Stefanski from leaving to become the Giants’ offensive coordinator, some in the media huffed and puffed about Zimmer’s failure to promote upward mobility in the coaching ranks. On Thursday at the Scouting Combine, Zimmer explained his reasoning for keeping Stefanksi in place. “Loyalty to me is a big thing,” Zimmer said, via Ben Goessling of the Minneapolis Star Tribune. “So I come in here four years ago and the offense is 29, 27th, 26th. But I keep them. So the first time our offense is pretty good, then I’m supposed to let all my coaches leave? . . . I don’t think that’s right. If I’m going to be loyal to them and not fire them after they don’t have good years, then I don’t think they should not be loyal to me.” It makes sense, and it underscores the reality that a contract is a two-way street.