How can I prevent injuries?
There are 2 main factors;
A player becomes more injury prone when fitness is lower. Use fitness cards to keep your star players topped up, and use rotation to give your other players a rest.
A players physical attributes (strength, stamina) also play a part. There are also 1 or more hidden characteristics for injury proneness, so if you notice a player who gets injured a lot, it might be time to replace him.