Race is on for Jonny Sexton's Ireland jersey
Madigan and Keatley go head-to-head at Thomond as Jackson returns for Ulster
Madigan would appear to be next in line for the job given he started against Georgia last month and came off the bench in the wins over South Africa and Australia, but the Leinster star has played most of his rugby in the centre this season.
Tomorrow, he has been given the nod to wear the No 10 jersey as Leinster take on Munster at 5.00pm.
His opposite number, Keatley, was the third choice in November after being selected ahead of Jackson who subsequently injured his shoulder.
The Ulster youngster replaces Ian Humphreys to partner Ruan Pienaar as Ulster look to keep their noses in front of the westerners and get their season back on track. His return is one of seven changes as Roger Wilson captains the side.
After staging a two-day camp in Maynooth earlier this week, Schmidt has withdrawn most of his frontline internationals from the Christmas equation, with Gordon D'Arcy the only member of the starting XV that beat Australia involved in either derby.
Leinster have still been able to name 12 internationals in their team to face Munster in Limerick, as Richardt Strauss returns from injury to make his 100th appearance for the province.
D'Arcy partners Luke Fitzgerald in the centre and Dominic Ryan returns to the back-row alongside No 8 Jack Conan and Shane Jennings who captains the side.
Munster coach Anthony Foley has recalled Duncan Casey, CJ Stander and Tommy O'Donnell to his side for the meeting of third and fourth, while Donncha O'Callaghan and Felix Jones are promoted from the bench.
Mils Muliaina has been dropped to the Connacht bench for their visit to Ulster as Ireland prospect Darragh Leader comes in at full-back, while Bundee Aki shifts to outside centre as Dave McSharry replaces Robbie Henshaw.