Looks like he was arrested on border, going INTO Canada with oxycotin pills. He didnt have prescription for it so cud be charged with smuggling.
Whichever side of the border he ended up at (and if he was arrested by the mounties, he must have been in Canada) he will not be able to travel to and from United States. Which is a significant hardship for an NHL player. So that would probably be the basis for Kings' terminating his contract, since he can't travel normally with the team. Convinient for them, but probably justified, so the NHLPA may not be able to reverse the contract termination.