no, it's not only you ...is it just me who gets the best players injured in important matches?
some say that the best players are more active so they are more attractive to oppo butcher-players
some say that it's random
some say that it's not random because if you have your best player injured, you 'll find a way to heal him because you need him
the other problem is that if you heal him with red packs, it's very possible to get injured again in the period he had the first injury.
I usually heal the player, leave him resting for 1 day and after that I use him, but only in one game - the most important (and of course no training).