its just random and honestly speaking pure luck...i dont know of any such number and i doubt it even exists.u dont need to worry.just believe that he was unlucky in getting injured so many times...
well the other possibility might be that ur player isnt good to many players off court so they just hammer him in the court so thats y he is injured.but since the game engine doesnt tell us about those kinda things so i cant tell if that has happened or not.;)