Irish lock James Ryan will face a race against time to be fit for Ireland's two remaining Six Nations games later this year.
Andy Farrell's side is due to take on Italy on 24 October and France a week later, to conclude the tournament that was postponed back in March due to the spread of Covid-19.
Leinster head coach Leo Cullen issued a squad update today and the 24-year-old is set to be out for up to three months.
He requires 10-12 weeks to recover from shoulder surgery.
Get well soon, lads. 🔵👊
— Leinster Rugby (@leinsterrugby) August 3, 2020
The update also revealed that Adam Byrne is set to be out of action for up to three months as well.
The 26-year-old winger has suffered a hamstring injury and is due to have a procedure on it this week.
This means both players will miss the Blues derby Pro-14 fixture against Munster at the Aviva Stadium on 22 August.
In good news from the province, prop Peter Dooley is expected to return to training in two weeks following a shoulder injury and Ireland flanker Dan Leavy is 'continuing to integrate gradually into rugby training after a significant multi-ligament knee injury'.