I'm not exactly sure how the injury thing works, but I know there was a huge problem in HD a few years ago that they ended up fixing. Guys who got injured for a long period took a ratings hit and lost valuable development time. A two month injury, regardless of the injury, would kill their career. I don't think that large of hit was intended, so they fixed it.
In HBD when a young player gets injured say for a half season or more, this can happen as far as I've experienced; the loss of development time seems to be the biggest hit, not the injury. I dunno, is it meant to be such a drastic hit to the player in this situation?