That's up to the manager to stop that. I've just never understood wanting our own players injured for any reason. As for McCarthy's injury, of course it's not life threatening but it's too early to say whether it's career threatening.
Oh well, it's only a career. What I don't get are the shouts of the injury being "horrible" and Rondon crying on the pitch. Any other sport it would be "gee, that's a shame" and then move on. With all the shit people across the world put up with every day, deadly diseases, poverty, wars, there's really no need to get the tissue box out for an injury to a millionaire.