Johnny Sexton will not return for Leinster's Guinness PRO14 Rainbow Cup clash against Connacht this Saturday.
The captain remains sidelined due to concussion after suffering three head injuries in nine weeks and missed his side's Heineken Champions Cup semi-final defeat to La Rochelle last Saturday.
After starting that game, Ross Byrne may be pressed into service again as his brother Harry remains sidelined with the hamstring injury he picked up against Munster two weeks' ago. He will be out for a further three-to-four weeks.
Ciarán Frawley was an unused replacement in France, while David Hawkshaw came off the bench in the Munster game but Byrne is the most experienced No 10 in the squad and the province are now fighting on one front.
Leinster will be without talismanic back-row Rhys Rudddock for the next four to six weeks after he pulled a calf in the first-half in La Rochelle.
Caelan Doris is rated doubtful for the trip to his native province, while fellow back-rows Max Deegan, Dan Leavy and Will Connors are on the long-term injury list.
Like Doris, Ireland scrum-half Jamison Gibson-Park is being managed after his hamstring problem and may not feature against Connacht.
Jimmy O'Brien is close to a return after his hamstring troubles.