6. Ben Cousins / Daniel Kerr
Back in 2002, Eagles teammates Ben Cousins and Daniel Kerr were witnessed having an argument outside a Perth nightclub, which was rumoured to be about Kerr's relationship with Cousins sister.
Cousins allegedly walked up to Kerr pointed his finger said "this is not over". Kerr's response prompted the punch, leaving Cousins with a broken arm. Both Cousins and the Eagles denied that the injury occurred from the fight, instead claiming that he fell down a flight of stairs.
Whilst the Carey / Stevens situation was ugly and involved the AFL’s highest profile player it occurred in the off-season and the 2 never played for the same team again so it was hardly a long running feud within the confines of the club. i’m surprised you never included the likes of Andrew McLeod / Tyson Edwards and Gary / Steven Hocking. Both combinations played 200+ games in the same team and rarely spoke to each other and had major personal disagreements with each other.