NHL's Mike Richards -- Charged with Drug Possession In Canada

Ex-L.A. Kings player Mike Richards has been charged with possession of a controlled substance over an incident involving prescription drugs ... TMZ Sports has learned.

As we previously reported, the Royal Canadian Mounted Police were investigating the NHL player for allegedly transporting Oxycodone across the border back in June.

Now, we've learned he's been charged with a crime -- and if convicted as a first time offender, he faces up to 6 months behind bars.