Sam Darnold spent one season with the Minnesota Vikings before signing with the Seattle Seahawks this past offseason. It isn't his fault that he is no longer with the Vikings; the team didn't want him back. Minnesota's loss has certainly been Seattle's gain.
In fact, while Darnold might not feel vengeful about not being welcomed back to Minnesota, the Vikings shouldn't feel the same. The quarterback was pushed out instead of wanting out. If one has a greater reason for a revenge game, it is Darnold.
Vikings defensive coordinator Brian Flores might not feel that way, though.