The NRL's integrity unit claims Mitch Kenny has brought the game into disrepute following an investigation into a social media post sent by the Penrith premiership player.
The NRL on Thursday issued Kenny with a breach notice after the Panthers hooker's early-morning social media offering on December 27 caused a stir.
The post, captioned "couple of Boxing Day lines have got me in troubleeee (sic)'', was deleted and soon followed by a second screenshot of a post that read, "Happy New Year guys. Enjoy and ignore trolls who grabbed my phone."
The Panthers acknowledged the breach notice in a statement and declined to comment further.
Kenny has five business days to respond.
A try-scorer in last year's grand final, Kenny is part of the squad preparing to fly to England for February 24's World Club Challenge against Wigan.
Cowboys star Valentine Holmes copped a fine and one-game suspension when his social media post last September showed him holding a small bag containing white powder - an incident he explained was a joke gone wrong.
