One way of reducing the amount of fouls is to train defense, so training ID will reduce the amount of fouls.
Another way could be to train stamina. Higher stamina means that his performance will be more consistent throughout the game, which means he won't tire as much and start performing poor, leading to fouls.
Another way could be to maintain high GS. The idea behind this is similar to the idea behind training stamina.
There's apparently agressiveness for every player, it's just not shown and we cannot see it. It could perhaps be that he is a very agressive player too.