Ruling on wearing shorts when playing sport and exercising
Question

                I play basketball, so I wear shorts when practicing and when playing in matches. Is this haraam?
Praise be to Allah.
    Playing sport is permissible if that does not distract one 
    from something that is obligatory. If it distracts you from something that 
    is obligatory then it becomes haraam, and if it becomes a person’s way of 
    life so that it takes up most of his time, then it is a waste of time, and 
    in this case at the very least it is makrooh.

     With regard to playing sport wearing only shorts which show 
    the thighs or most of them, this is not permissible. The correct view is 
    that young men must cover their thighs, and it is not permissible to watch 
    players when they have their thighs uncovered in this manner.