The Vikings at some point in the coming weeks figure to add another quarterback to their 90-man roster. Right now, they have only three, one of whom might not be cleared to throw a football any time soon. With Teddy Bridgewater’s status in limbo due to the devastating knee injury he suffered last August, the Vikings have no proven backup to Sam Bradford, whom coach Mike Zimmer named the starter in January. Shaun Hill, who started the season opener last year before making way for Bradford, is a free agent.