Q: Can I still play a player whose health is less than 100%?
A: Yes. Depending on the type and severity of the injury, you'll see the player's health drop. If a player's health drops below 50%, he'll be forced to sit out until his health is at least 50%. Once his health is above 50%, you can choose to rest that player by setting his target minutes to 'rest' (only injured players may be rested). If you choose to rest him, he will not dress for the next game, but he will continue to practice. If you choose to play him, he may not be as effective due to the type/severity of his injuries. Playing him while injured may also increase his chances of further injury.
I always thought if you put him at "rest" he would not practice and his ratings would go down. Is the FAQ wrong here?
(Edit) Answer : FAQ is correct. Practice time is impacted by the extent of the injury, not whether he is set at "rest" or not.