Ian Madigan came off the bench in Ireland's victory over France
Fly-half Paddy Jackson will miss Ireland's summer tour to Argentina, the IRFU have confirmed, with Ian Madigan replacing him in Joe Schimdt's squad.
Jackson, 22, enjoyed a fine run of form in the closing stages of Ulster's season but due to a stress fracture in his lower back, he will stay at home this summer.
Jackson, who came off the bench in four of Ireland's RBS 6 Nations matches this summer, has been battling the problem for some time, but the injury has deteriorated and he was unable to train at the Ireland mini camp which took place in Dublin this week.
An IRFU statement read: "The injury will require rest and recuperation for Jackson to start next season fully fit. Ian Madigan has been confirmed as his replacement on the tour."
Madigan was originally omitted from Schmidt's 30-man squad with the New Zealander opting to take just two fly-halves to face the Pumas - Jonathan Sexton and Jackson.
As a result, Leinster's Madigan was set to tour Romania with the emerging squad but he was now been seconded to the seniors.
After losing their Under-20s Six Nations crown to England Under-20s in a thrilling final round, France Under-20s lock Tristan Labouteley insists his side will be out for revenge at this year's Junior World Championship.