A dirty player is the same as a jerk or a selfish arse or a manipulator or a schemer or whatever..
THey're great to have on your side, but the devil if they wear the other jersey.
I used to play rugby with one mens club. I play in the pack, kinda like the offensive line. Another guy in the pack, this older body builder would always get into a fight every game over some allegation of dirty play or another. It was alwayts an event and somehow it always galvanized our team.
Then, I played him as an opponent. Everything was fine until in one ruck he grabbed my balls and twisted them. I have not been able to look at the guy since. What a jerk. That is the dirty player double edged sword.