If you're wondering what the significance of the Spaceman Lee and the Brockton Rox is, check it out.  
One might think that Bill would be the oldest to compete in a pro game, but no.  Minnie Minoso is the only player to bat professionally in each of 7 decades, with his most recent plate appearance coming with the St Paul Saints in 2003.  At 77, he drew a walk.  Jim Eriotas struck out to lead off a 2006 Sioux Falls Canaries game. Despite it being his first pro at-bat, the 83 year old claimed aftewards that if he got 4 MLB at-bats he could produce a hit.  Negro League legend Buck O'Neil drew intentional walks to lead off both halves of the 1st inning in the 2006 Northern League All-Star game (don't ask).  O'Neil was 94 and would pass away less than 4 months later.  Another Negro Leaguer, Ted "Double Duty" Radcliffe died in 2005 at the ripe, old age of 103.  103!  What?  Yet, DD was a spring chicken of 96 when he tossed a single pitch for the Schaumberg Flyers in 1999 to set a standard for elder statesmen that has yet to be equaled.