Blue

The protagonist was a star basketball player, looking forward to a bright future as a sportsman.
But then he injures his right knee and the doctor's diagnosis turns out to be for him to refrain from hard exercise.

Two years later he has overcome the odds and partially recovered, once again being able to play basketball. Even so, because of his measly height he isn't able to pursue a career in the sport he loves. He regrets nothing and continue to attend school, hanging out with his friends.