England winger Mark Cueto faces the prospect of a lengthy ban after he was cited by the Rugby Football Union for "making contact with the eye or eye area" of Northampton's Christian Day.
The 31-year-old will appear before an RFU Disciplinary Panel on April 11 to answer a charge that carries a minimum ban of 12 weeks.
While such a punishment would severely hinder his preparations ahead of the World Cup, the RFU also have scope to ban Cueto for more than 24 weeks if found guilty of a top-end offence.
The World Cup begins in New Zealand on September 9, meaning a long-term ban could potentially rule him out of the tournament.
Northampton hooker Dylan Hartley missed the previous World Cup in 2007 after he was banned for 26 weeks after being found guilty of a similar offence.
Cueto was cited by the independent citing officer Matt Bayliss and will appear before an RFU Disciplinary Panel that will be chaired by Antony Davies and also include Clif Barker and David MacInnes.
Cueto clashed with Day during Sale's Aviva Premiership match on April 2.