Carlson departed the Vikings' 21-14 victory over the Arizona Cardinals after reporting concussion-like symptoms. He did not return, and coach Leslie Frazier said the team will spend the next 48 hours confirming the initial diagnosis. If Carlson did suffer a concussion, it would be his second in eight games and the fourth of his career dating back to his time at Notre Dame.
NFL teams are appropriately and increasingly raising their scrutiny of repeated concussions, as we in the NFC North know full well as the Detroit Lions await progress from tailback Jahvid Best. Carlson's most recent concussion came on January 16, 2011, while playing for the Seattle Seahawks in the NFC playoffs. He was knocked unconscious on the play after trying to leap over Chicago Bears safety Danieal Manning and spent the night in a Chicago-area hospital.
Carlson didn't play another down for the Seahawks because of a shoulder injury that cost him the 2011 season.
To be clear, we don't know for sure that Carlson suffered a concussion Sunday. And if he did, we can't make any dramatic conclusions about his immediate availability or the direction of his career. But Carlson was a significant free-agent acquisition who signed a five-year contract worth $25 million last spring. As a rule in 2012, even the mere possibility of a fourth concussion for an NFL player should be considered with context.