Leinster head coach Leo Cullen has told 98FM Sport that there is a "strong possibility" Sean O'Brien will be fit in time for the province's Guinness PRO12 semi-final.
The Blues flanker was a late withdrawal ahead of the Champions Cup semi-final defeat to Clermont Auvergne in Lyon just over two weeks ago.
"Sean's going good yea, he's back running so we'll see how he comes through next week", Cullen told 98FM Sport's Stephen Doyle ahead of the last-four clash with Scarlets at the RDS on Friday week.
"I think there's a strong possibility that he will be [available for the PRO12 semi-final] yes. He's making good progress and we'll just see how he goes.
"He's been running away and we'll introduce him back into rugby now next week so we'll just see how he progresses through that."
Cullen admitted that Jamie Heaslip was "less likely" to be involved in the Scarlets game after the number 8 underwent surgery on his back.
The Blues gaffer was pretty downbeat when asked if it was possible that the Ireland vice-captain could be fit in time to join his fellow men in green on their Summer tour to the USA and Japan.
"I'm not sure. Obviously everyone wants to be involved with Ireland any chance they get but it's getting very, very tight for him and he's not back on the field yet so his chances would be looking a hell of a lot less likely."
Cullen was quite positive with regard to Robbie Henshaw who had a rib injury but has returned to training after being left out of the Ulster defeat last weekend as a precaution.