EHM The Blue Line

So, Recently, while playing as the Senators, I traded for Alex Burmistrov, and he currently plays in Russia, but I own the rights to him, all is good, I don't exactly have room for him on my roster, and it's good he's over there playing there, but my question is, how do I retain the rights of a player, and have him play in Europe?

I have the Rights to Oskar Lindblom, after having drafted him, and if I sign him, and if I don't find room for him on the roster, or he doesn't make the team, will I be able to send him back to Europe to play

Also, if someone could clarify how Arbitration, and the RFA system works within the game, that'd be great!