Leinster out-half Harry Byrne has been ruled out of Saturday's United Rugby Championship meeting with the Scarlets at the RDS.
The 22-year-old suffered a hip injury during the first half of his side's 43-7 win against Zebre, and is currently being assessed by the province's medical staff.
Byrne was making his first appearance of the season when he picked up the knock against the Italians, having missed the opening two rounds of the URC with a foot injury.
Speaking after their comfortable win against Zebre, head coach Leo Cullen said it's been a difficult period for the Ireland international.
"He's frustrated, he just needs to get himself right," Cullen said
"He takes a heavy bang in the hip and that just sometimes happens, these things happen. It stiffened up quite quickly."
Meanwhile, centre Rory O'Loughlin has been ruled out for the second week in a row with a shoulder injury.
The 27-year-old picked up the knock in their round two victory against the Dragons, and the extent of the damage is still being assessed.
Centre Ciarán Frawley and flanker Scott Penny are doubtful for the visit of the Welsh side this weekend, with both players picking up dead leg injuries.
In better news, number eight Caelan Doris has stepped up his recovery from a calf injury and took part in training today, with a call to be made later in the week on his availability for the meeting with Scarlets.
Flanker Josh Murphy is back in full training after sitting out the opening three games with a similar calf issue.
Follow Munster v Connacht (Saturday 7.35pm) via our live blog on RTÉ.ie/sport or the RTÉ News app, or watch live on RTÉ2 and RTÉ Player. Watch Ulster v Lions (Friday 7.35pm) on RTÉ2 and RTÉ Player.
