London - England hooker Dylan Hartley risks missing the World Cup after the Rugby Football Union (RFU) announced on Tuesday that he faces a disciplinary hearing on Wednesday over an alleged headbutt.
Hartley, capped 66 times by England, was cited for striking an opponent with his head during Northampton's 24-29 defeat at home to Saracens in the English Premiership play-offs last Saturday.
The New Zealand-born 29-year-old, who has been suspended five times in his career, will face a ban of between four and 12 weeks if found guilty by a three-man panel in Coventry, central England.
"Hartley was cited following the Premiership semi-final match between Northampton Saints and Saracens for striking an opponent with his head, contrary to Law 10.4(a)," the RFU said in a statement.
Hartley was named in England's 50-man World Cup training squad last week, but head coach Stuart Lancaster has previously warned that he could be thrown out of the squad permanently if his on-field conduct did not improve.
Less than two weeks ago, Lancaster ruled Manu Tuilagi out of the World Cup after the Leicester centre pleaded guilty to assaulting a police officer.
But regardless of Lancaster's reaction, with Northampton's season having ended, any ban for Hartley would be unlikely to start before England begin their World Cup warm-up programme in mid-August.
Lancaster will name a final 31-man squad in late-August, before the hosts launch their World Cup campaign against Fiji at Twickenham on September 18.
In total Hartley has been banned for 50 weeks during his career, including a 26-week suspension for eye-gouging in 2007 and an eight-week ban for biting in 2012.
Two years ago, he was banned for 11 weeks after being sent off for abusing referee Wayne Barnes during the Premiership final against Leicester, causing him to miss the British and Irish Lions' tour of Australia.
Leicester's Tom Youngs is expected to be Lancaster's first-choice hooker at the World Cup, but the England coach would be loath to lose a player of Hartley's experience.