Cullen in for McCarthy
Ireland captain Nick McCarthy has been ruled out of the remainder of the U20 World Cup with a shoulder injury.
The scrum-half's leadership has been a vital ingredient of coach Nigel Carolan's game plan, especially in light of first-choice out-half Ross Byrne's late withdrawal from the competition.
This means Charlie Rock will be the logical option to step in at nine with Munster's Jack Cullen called out to Italy as a back-up.
Flanker Josh Murphy will take over the role of captain ahead of Ireland's 5th-8th place play-off against Wales in Viadana on Monday (7.30pm Irish time).
The Irish will be out to make amends for their Six Nations defeat to Wales.