Johnny Sexton has been ruled out of Leinster's Heineken Champions Cup semi-final against La Rochelle on Sunday, the province confirmed this afternoon.
Sexton was withdrawn after undergoing a Head Injury Assessment (HIA) in the first half of Leinster's quarter-final victory away to Exeter Chiefs over a fortnight ago.
He sat out Saturday's Rainbow Cup loss to Munster and Leinster confirmed this afternoon that the Ireland out-half is unavailable for selection against La Rochelle and "will continue to train and be assessed as part of the Graduated Return to Play process".
The 35-year-old suffered a prior head injury in Ireland's Six Nations opening weekend defeat against Wales and missed the subsequent game against France. However, he returned to star in Ireland's trio of victories against Italy, Scotland and England.
He was replaced against Exeter by Ross Byrne, who delivered an assured performance as Leinster eliminated the reigning European and English champions on their own turf.
Byrne was not risked in last weekend's game against Munster and will likely start on Sunday.
Elsewhere, back-row Caelan Doris (calf injury), scrum half Jamison Gibson-Park (hamstring injury) and out-half Harry Byrne (hamstring injury) remain injury doubts heading into the weekend.
All three will be further assessed later in the week.
James Ryan and Garry Ringrose, however, are both available for selection after returning to action after injury against Munster last weekend.
