Wasps have confirmed their England international back Elliot Daly has suffered a medial knee ligament tear, while team-mate Matt Mullan faces three months out with a torn tricep tendon.
Daly and Mullan were unable to travel to an England training camp with the rest of Eddie Jones' squad after they were hurt in Saturday's 38-22 Premiership victory over Northampton Saints, with Semesa Rokodoguni called up to replace the former on Monday.
Later that day, a Wasps statement shed light on the extent of Daly and Mullan's respective injuries.
It read: "Elliot Daly suffered a grade two MCL tear [Medial Collateral Ligament - knee]. The club will continue to treat him this week and assess how the injury settles. He is then expected to undergo a two to three-week period of rehab.
Matt Mullan and Elliot Daly injury update here. Wishing both as swift a recovery as possible! https://t.co/xrUupS7PGl-- Wasps (@WaspsRugby) October 30, 2017
"Matt Mullan has torn a tricep tendon which will require surgery. It is unfortunately anticipated that he will be sidelined for approximately three months."
The versatile and pacy Daly impressed on the British and Irish Lions' recent tour of New Zealand and has swiftly established himself as a key figure in England's team since making his debut in February 2016.
Prop Mullan has earned eight caps - predominantly off the bench - since Jones took charge, taking his total number of international appearances to 17.
England face Argentina at Twickenham on November 11, with matches against Australia and Samoa on the following Saturdays.