Owen Farrell and Joe Marler could both miss England's three-Test tour of Australia in June after being cited Monday for alleged disciplinary offences while on European duty with their respective club sides last week.
Farrell could also be sidelined from Saracens' bid to be crowned kings of Europe in next month's Champions Cup final after being cited Monday for a dangerous tackle.
Meanwhile Marler, already banned once in a season where both he and Farrell helped England win the Six Nations with a grand slam, found himself in fresh disciplinary trouble after being cited for kicking an opponent playing for Saracens' London rivals Harlequins.
Farrell was alleged to have committed a dangerous tackle on Wasps' scrum-half Dan Robson early in the second half of Saracens' 24-17 European Champions Cup semi-final win over their fellow English club in Reading, southwest of London, on Saturday.
Saracens fly-half Farrell was shown a yellow card by French referee Romain Poite for the head-high challenge and spent 10 minutes in the sin-bin.
But he now faces a hearing after Italian match citing commissioner Stefano Marrama made an official complaint.
If he is found to have contravened World Rugby's sanctions on foul play, Farrell could face anything from a two to 52-week ban, although he is unlikely to be hit with the most severe penalty.
But even a low or 'mid-range' ban of six weeks could rule Farrell out of the May 14 Champions Cup final against Paris's Racing 92 in Lyon, where Premiership leaders Saracens will be bidding to be crowned champions of Europe for the first time in their history.
Any longer suspension could also have an impact on Farrell's availability for the Australia tour.
Saturday's match also match saw Wasps replacement Simon McIntyre, who like Farrell was yellow-carded, cited for allegedly kicking England lock Maro Itoje in the 69th minute at Reading's Madejski Stadium.
Meanwhile Marler, playing for Harlequins in their 30-6 win over Grenoble in the semi-finals of the second-tier European Challenge Cup on Friday, has been accused of kicking the French club's hooker, Arnaud Heguy, by Scottish citing commissioner Iain Goodall.
In common with Farrell, Marler too now faces missing out on the Australia tour if suspended.
The 25-year-old front-row forward was playing for the first time Friday since serving a two-match ban for his "Gypsy boy" slur against Welshman Samson Lee in the Six Nations.
After the match, Harlequins boss Conor O'Shea defended Marler by saying:
"Any test for a citing has to pass the red card test, and this does not pass that test.
"Should he do it? No. Is it a red card? No," said former Ireland full-back O'Shea, who will leave Harlequins at the end of the season to become the new Italy head coach.
Marler initially escaped censure for his taunts against prop Lee in England's 25-21 Six Nations victory over Wales at Twickenham on March 12.
Global governing body World Rugby later intervened and called a misconduct hearing however, dissatisfied with the leniency of Six Nations and RFU bosses.
Marler admitted the charge and was banned for two matches and fined £20,000 ($29,000).