In New York, Drury and Gomez both wore 23, so they flipped a coin to see who would get it. Drury won it and Gomez took 19.
I can't imagine many players would refuse to play for a team without having their number. I've also read a lot of stories from vets coming to a team and they don't even ask for their number, saying the player who was wearing it could keep it, but usually the younger player shows the respect and offers up his number anyway, a la Kopecky, Franzen, et all.