What is the word for this type of person?

There is a guy in my fantasy football league and all he does is literally roots the teams the teams that his fantasy players are on. Ex: last year he loved the packers because he had Aaron Rodgers and the packers D. This year he loves the texans because he has Andre Johnson on his fantasy football team. I've known him for a long time and he never was a packers or texans fan before he had those players on his fantasy team. Is there a name for a person like this? If so, what is it?