Jan 18, 2012 – Across the histories of Major League Baseball, the NFL, the NBA, the NHL, and NCAA football and basketball, there have been a total of 1,884 athletes who primarily went by the name Bob. Not Robert, or Bobby, but Bob.
Via Wikipedia, the story of how San Diego Chargers safety Bob Sanders came to be known as Bob:
Having been given a name that was difficult for many to pronounce correctly (Demond), Sanders asked his mother if his name could be changed. His mother suggested “Bob” as a nickname, and the name stuck.Of those 1,884 Bobs, Sanders is the only one still playing.