The Fiji international, 25, faces a disciplinary hearing on Wednesday.
He is accused of "lifting a player from the ground and dropping or driving that player into the ground" when tackling Gareth Owen in the 51st minute.
World Rugby's recommended bans for those found guilty of such offences range from four to 52 weeks.
Ospreys' next match sees them host Dragons on New Year's Day at the Liberty Stadium.
If banned, Matavesi could also miss the Pro12 trip to Leinster on Friday, 8 January as well as their crucial European Champions Cup game that follows at Clermont Auvergne on Friday, 15 January.
Ospreys centre Josh Matavesi has been cited for an alleged dangerous tackle during Boxing Day's 27-26 Pro12 win at Scarlets in the west Wales derby.