Indeed, sometimes it just happens. I had Wayne Rooney fully fit and he got his ribs broken during the first EPL game and was out for about 5 weeks. Then I conditioned him back to full fitness and he promptly got himself injured again and was out for a month :'(
But I still suggest that you learn the use of shouts. If nothing else, it will help you conserve their fitness.
But I still suggest that you learn the use of shouts. If nothing else, it will help you conserve their fitness.