"The timeline would be right because they were waiting till after the internationals to conclude these things," said ex-Munster and Leinster lock Trevor Hogan on Off The Ball's Monday Night Rugby.
"But I think the IRFU will throw another few weeks at it. It would be a massive loss. You'd hope the IRFU won't let that happen."
But it is the attritional nature of the French Top 14 which is the most worrying aspect of a potential move for the duo according to former Ireland head coach Eddie O'Sullivan on MNR tonight.
"O'Brien is one of those players that can play at such a high tempo and is always in collisions. For him to come through the Top 14 without injury would be a miracle. It's hard to believe that he can have a long career playing in the Top 14. Leinster have responded brilliantly to the loss of Isa Nacewa and Jonny Sexton, but losing Heaslip and O'Brien...you can only sustain a hemorrhage to a certain degree. That could be a tipping point for Leinster."