Just curious, did the Rebbe ever say an opinion on wether or not a frum yid should be following professional sports?
I don't think you need an opinion from a Rebbe for this one.
It's a Posuk.
ואהבת את ה''א בכל לבבך, ובכל נפשך, ובכל מאדך.
It's either part of that in which case it's good, or beyond that, in which case there's no room for it.