Jack Conan is set to miss Leinster's trip to Munster in the URC this Saturday.
The back-rower did play through a knee injury in their interpro win over Ulster last Friday, but he is now a doubt for the game in Thomond Park.
In more positive injury news, Andrew Porter, Will Connors and Charlie Tector are available for selection this weekend.
Ulster have secured the services of forward Cormac Izuchukwu until the summer of 2028.
The Offaly man made the first of 44 appearances for the province back in 2021, while also earning three Ireland caps.
He is expected to be fit for Saturday's trip to Connacht, as is centre James Hume.
But second-row Charlie picked up a calf injury last weekend at Lansdowne Road, and has been ruled out.
An Ireland XV will take on England 'A' in Limerick's Thomond Park next February.
The development side last faced Spain in November, and Ireland 'A' lost to England 'A' in Bristol during last spring's Six Nations window.
The game, next spring, takes place the day after Andy Farrell's side open their Six Nations campaign against France in Paris.
