The Minnesota Vikings made significant investments in their interior offensive line during the offseason in an effort to become a more physical offense. Once left tackle Christian Darrisaw made his season debut, the full starting offensive line would stand among the best in the NFL. One injury concern on the Minnesota Vikings offensive line uniquely stands outIf O'Neill has a significant injury to his MCL, he will be out for a while, and his absence will be just as significant as Darrisaw's was. But even with that in mind, there's an injury concern for the Vikings' offensive line that stands out. But there has to be some real concern about Kelly right now, beyond how the Vikings are in line to be without him again.