Yeah.. Rookies become part of the players union, their NFL players aren't they?
And yes all players become part of the union because its the PLAYERS union....
they do not have to be part of the nflpa but they do have to be part of the union, this is what protects the plays and gets them their annual salary, but the nflpa is different if you have ever played madden bill parcells or bill belicheck are not in the games because they refused to have their name used in brand marketing. Although 99 percent of players are in the pa for merchandise sales