Can you train a guy while he's injured and then play him?
If you know a way to let an injured player play, please let me know ;)
If a player is injured for the complete week, and you can't let him play at all, the only way to train him is by using the "teamtraining" option and train Stamina, Free Throws or Game Shape. If he already has played some minutes, or will be fit again in time for your cup/scrimmage game you will be able to give him training for the minutes he actually played that week, regardless if he is injured or not at the time of the training update.