Jackson, who endured a mixed afternoon when deputising for the injured Jonathan Sexton against Scotland, has suffered a hamstring strain that has placed his participation in slight doubt.
The uncertainty over the 21-year-old's fitness and the presence of the in-form Madigan has prompted coach Declan Kidney to delay naming his selection for the number 10 jersey and who will supply cover from the bench.
Sexton was set to be recalled but it has been decided to give him a further week in his rehabilitation from a hamstring injury.
"Paddy's chances of pulling through are very good and he should be good to train on Thursday," Kidney said. "We'll make the choice between Paddy and Ian then. I was told just a moment ago that it will be better to give Jonathan Sexton another week to recover."
In total there are three confirmed changes to the starting XV defeated by Scotland, among them Fergus McFadden's selection on the right wing after Craig Gilroy failed to recover from his groin strain.
Cian Healy is restored at loosehead prop after completing his suspension for stamping against England on February 10, replacing Tom Court. Lock Mike McCarthy has recovered from the knee ligament damage sustained in the loss to Stuart Lancaster's Grand Slam-chasing team, so Donncha O'Callaghan drops down to the bench.
Donnacha Ryan continues in the second row after passing a fitness test on his bruised shoulder, but substitute prop Declan Fitzpatrick has been ruled out with a calf strain and his replacement has yet to be announced.
Ireland team: R Kearney (Leinster); F McFadden (Leinster), B O'Driscoll (Leinster), L Marshall (Ulster), K Earls (Munster); AN Other, C Murray (Munster); C Healy (Leinster), R Best (Ulster), M Ross (Leinster), M McCarthy (Connacht), D Ryan (Munster), P O'Mahony (Munster), S O'Brien (Leinster), J Heaslip (Leinster, capt).
Team: 15-Rob Kearney, 14-Fergus McFadden, 13-Brian O'Driscoll, 12-Luke Marshall, 11-Keith Earls, 10-Paddy Jackson/Ian Madigan, 9-Conor Murray, 8-Jamie Heaslip (captain), 7-Sean O'Brien, 6-Peter O'Mahony, 5-Donnacha Ryan, 4-Mike McCarthy, 3-Mike Ross, 2-Rory Best, 1-Cian Healy
Replacements: 16-Sean Cronin, 17-David Kilcoyne, 18-Stephen Archer or Michael Bent, 19-Donncha O'Callaghan, 20-Iain Henderson, 21-Eoin Reddan, 22-Paddy Jackson/Ian Madigan, 23-Luke Fitzgerald.