Hard to tell for that particular player because of a small amount of games, and overall much lower skills than the opponents.
But I am starting to believe that aggressive players do play defense better than their skill level. I have two aggressive players who start on my team, and I think they definitely overperform in terms of steals and defense, despite their moderate defensive skills.
So, there may be some positive effects of aggression. The question is do I want to spend my training spots on that type of guy?