Leinster are facing an anxious wait over their top two no 10s ahead of Friday night's Champions Cup last 16 tie with Toulon, while James Ryan is ruled out.
Harry Byrne is waiting in the wings to see if he will be called upon by Leo Cullen for the RDS clash after missing out on last Saturday's PRO14 final victory over Munster.
Harry's older brother Ross started and finished that 10-point victory, after having to come back on for Johnny Sexton, who needed a HIA just five minutes after coming on and didn't return.
Byrne took a knock to the knee in the second half and is being assessed, while Sexton has entered graduated return to play protocols and will also be assessed.
Sexton missed Ireland's clash with France after failing to successfully go through all the protocols, having taken a head knock against Wales in the Six Nations opener.
Pack leader Ryan remains sidelined after suffering a concussion against Scotland, while Leinster's top scorer in the PRO14, Scott Penny, remains out with a hand injury.
