The Minnesota Vikings have some concerns about quarterback Sam Bradford's left knee but remain cautiously optimistic about his status for Sunday's game, a source told ESPN on Friday. Bradford on Tuesday had an MRI on the knee after another source told ESPN that the quarterback had experienced swelling, pain and discomfort following Monday night's victory over the New Orleans Saints. The source said the MRI did not reveal any specific damage but that scans do not always offer a clear picture in a knee that has undergone multiple ACL repairs.?It is the same knee that underwent ACL repairs in 2013 and 2014, when Bradford was with the Rams. On Friday, coach Mike Zimmer would not comment on the report. "I'm not going to talk about who has had MRIs or who hasn't had MRIs," Zimmer said. "Lots of guys have MRIs." Bradford has been listed as a limited participant on the team's practice reports all week, but the source said the thought was that Bradford...