Sean O'Brien Out Of Leinter's Meeting With The Scarlets.
A calf injury has ruled Sean O'Brien out of tonight's Guinness PRO-12 semi-final against the Scarlets at the RDS.
The Lions flanker had originally been named among the replacements and his place on the bench now goes to Ross Byrne.
Leinster are favourites to progress to the showpiece final at the Aviva Stadium next week
Kick off is at 7.45pm.