Leinster head coach Leo Cullen revealed Jonathan Sexton will returning from injury in two weeks, while fellow Ireland internationals Sean O'Brien and Robbie Henshaw should return to action in October.
Sexton missed Ireland's tour of South Africa due to a shoulder injury, but the talismanic fly-half is close to making his comeback.
Flanker O'Brien was also unable to face the Springboks after sustaining a hamstring injury which required surgery, while centre Henshaw was ruled out of the decisive third Test in June with a knee problem.
Cullen was able to give a positive update on the trio's condition as last season's runners-up Leinster prepare to start the new Pro12 campaign with a home clash against Benetton Rugby on Friday.
"Johnny is making good progress. He's a couple of weeks away, probably," Cullen said. "Robbie and Sean, post their surgeries - Robbie had his operation after the tour [of South Africa] - they're making good progress.
"You're probably looking at six weeks with Robbie. Seanie had his surgery at the end of the last season. It was probably the most major of the surgeries out of the three of them. He's probably on a similar timeline to Robbie at the moment."
Asked if Henshaw and O'Brien would be available for Leinster's Champions Cup opener against Castres on October 15, Cullen added: "We'll see what's best for them. We're just making sure they get back correctly and we're not putting them at risk.
"They're making really good progress the two of them. You would hope to have them available, but if they're not right, they're not right."