Don't recall seeing any sports reporters referring to basketball players as "cagers" for a long time, but it certainly used to be very common, due to the early days of pro basketball being played in cages. There was a good Sports Illustrated article on the subject back in 1991. See In the early days of pro basketball, the players were - 11.11.91 - SI Vault for more than you ever wanted to know about the history of basketball played in cages by cagers.