Spencer Leniu faces at least a two-match suspension after being charged with grade-three contrary conduct on Monday morning.
The Parramatta Eels recruit will miss two games if he accepts an early plea, or could be banned for three if found guilty by a panel.
The charge followed Samoa's World Cup loss to Australia on Sunday, where Leniu was sin-binned after an exchange with referee Adam Gee.
What Leniu said to Gee has not been disclosed, though he appeared to make a money gesture while leaving the field.
Channel 7 sideline reporter Shaun Johnson said Leniu "made a beeline" for Gee before halftime.
Earlier, Leniu lost possession early in the tackle count before Australia scored its third try, then became involved in an on-field melee.
Gee brought Samoa captain Jarome Luai and Australia captain Isaah Yeo together during the confrontation.
Samoa needed a near-perfect effort from its leaders to challenge the Kangaroos, and the premiership-winning forward could have been a key bench option.
However, Leniu's aggressive style can sometimes go too far, leaving him set to start his Eels career on the sidelines.