In Michael Farfan, the Seattle Sounders find low-cost depth in the attacking midfield. A tendency for fouling limits his adaptability to deeper, defensive roles than he has played in the past.
Fan concepts of "dirty" and "clean" players often reflect perception bias. Fouls and cards mostly occur in place of defensive actions - either a duel crosses the line or the duel loser retaliates. The most frequent fouls come from the most frequent defenders. Attacking players are often more likely to commit a foul in a given duel, whether that's due to lesser defensive skill, referee bias, or the simple fact that the attacker is often not initiating the duel leading to a foul.