Unfortunately, that's the only good video that can be found, but in his final game in an Everton shirt, Cahill got in a tiff with Newcastle United's Yohan Cabaye. It was -- at least according to Evertonians -- because Cabaye was bullying a ball boy. Cahill earned himself a red card and a three game suspension for sticking up for the boy.
Now FIFA has some rules on this (warning, it opens a PDF)...
Any disciplinary suspension imposed on a player prior to a transfer must be enforced or applied by the new association at which the player is registered. The former association is obliged to notify the new association of any sanction in writing and upon issuing the (international transfer certificate).
So it gets a little tricky. MLS isn't US Soccer, but MLS does compete in FIFA sanctioned events. So the FA is required to tel US Soccer (or MLS) about his suspension, but, how does it get enforced? Will it get enforced? And what counts as a suspension? Does Saturday's game against the Montreal Impact count, since he's signed? What about the Tottenham Hotspur friendly next week?
It's not as if this team isn't used to dealing with personnel snafus, as evidenced by, oh, I don't know, this entire season. But you don't bring a player on as a DP and keep him on the bench.
Anyway, there's no doubt Cahill will have an impact when he takes the field. The only question now is...when?