Wales captain Sam Warburton is in danger of missing the autumn internationals due to a cheekbone injury.
The Cardiff flanker picked up the problem after clashing heads with Leinster's Josh van der Flier on Saturday, as the Irish province won 16-13.
Warburton left the field after 13 minutes at the Arms Park and will now have a scan on Monday to assess the damage inflicted in the incident.
If a fracture is confirmed, he will likely need eight weeks to recover and could be forced to miss his country's November internationals against Australia, Argentina, Japan and South Africa.
Interim Wales boss Rob Howley, who is due to deputise in the absence of British & Irish Lions boss Warren Gatland, already has doubts about his back-row.
Warburton's colleague Taulupe Faletau is currently struggling with a knee ligament which he picked up on his Premiership debut for new club Bath on September 3.