A bit late cause *away* but thank you for the feedback. I was suspectng that higher defense players were less "foul-prone" therefore there's little I can do expect buy someone else.
Seeing that it also happen in very important games of yours seem to correlate that fact that these players struggle with fouls when facing stronger opposition (which is perfectly logical as your colleagues pointed out earlier).
I didn't think of stamina however, I might give it a try, that's true that he isn't too heavy on that.
@Westri : if this turns out as it should, once your player os correctly levelled up defense-wise, you're trading trouble now for reward later, which is usually a worthwhile trade :p