Heaslip could line up against Racing Metro 92 in Paris on Thursday but it will come too late for Kidney who will likely name the British and Irish Lion in his squad on Wednesday and keep his fingers crossed the ankle repairs itself in time for Ireland's trip to Italy.
Club understudy Sean O'Brien, who holds four Ireland caps to his name, produced a man-of-the-match display against the Premiership outfit in Heaslip's absence.
And though the 23-year-old has been linked with a move to English side Bath, Leinster boss Josef Schmidt hinted he was on the verge of extending his stay at the province.
"I'm pretty sure we'll get some good news about Seanie in the very near future," said Schmidt.
"I'm not sure what it's going to cost Leinster or the IRFU but he looks pretty good value for money at the moment.
"His energy -- he's so dynamic that he just inevitably has an impact.
"He is abrasive, he does carry with a real energy. The rough edges contribute to who he is and those little bits of subtlety he has can surprise teams and it does offer us a little bit of space when he does offload."