Rhys Ruddock's season looks likely to be over due to the calf injury he sustained against La Rochelle in the Champions Cup semi-final last Sunday.
The first half loss of the experienced Ireland back row was a blow to the Blues, who eventually went down 32-23 in France.
Harry Byrne is also unavailable for the coming weeks, with the out-half suffering a hamstring injury just five minutes into the Rainbow Cup opener against Munster.
Johnny Sexton remains absent as he goes through his concussion protocols and now Byrne will be out for three or four weeks, but Leo Cullen will at least have Ciarán Frawley available as back-up to Ross Byrne for Saturday's clash at Connacht.
Frawley, who was on the bench in La Rochelle, has recovered from a hamstring injury and is training fully again as Leinster go through five days of quarantining together after arriving back from France on Sunday night.
Rowan Osborne has also returned to full training and is available for the Sportsground clash.
But Jamison Gibson-Park, who is still being managed with a hamstring injury, Caelan Doris - who suffered a minor calf injury prior to the Munster game and is still being assessed - and Jimmy O'Brien, working his way back from a hamstring issue, are not expected to be involved.
