San Francisco 49ers receiver Michael Crabtree recently said he lost vision temporarily following a hard hit during the final moments of Super Bowl XLVII.Significant story? No big deal?Crabtree, who made the revelations to NFL Network, opened another small window into the life of an NFL player. Crabtree said such things happen "all the time" and that he had not suffered a concussion. A check of records shows Crabtree has never appeared on an NFL injury report for injuries relating to anything other than a knee, foot or illness.