Poor Grades vs. Physical Activities - (Grades vs. Sports)

I believe that poor grades should affect the sports that that person does, one example of this would be if someone failed a class and they get kicked out of the hockey team that they played. The reason I believe this is fair is mostly because of my biased opinion that education is one of the most important things, and if you fail a class then you should spend time to increase your grade. It's also part my other biased opinion of not really liking sports too much, so I wouldn't really know how it would feel to get kicked out just because flunked biology... or something. So because almost all of my opinions are biased, I can't really give a legitimate response to that question...