From the start of last season to the very end, he was not the Rudy we saw during his breakout year. That isn't a slump, that's regression. Now you may be correct in saying it had nothing to do with playing for his national team, but if that's the case then I guess CL is right saying Rudy is what he is.
His regression had three parts: (1) injury recovery (2) gameplanning offenses around him and (3) actual regression. He did not have the same energy or enthusiasm for the game.