English referee Chris White has been forced to withdraw from Saturday's opening Six Nations clash between Ireland and Italy.
White is suffering from a calf complaint and is unable to officiate at Croke Park, with his duties being passed on to South African Jonathan Kaplan.
White was also due to run touch for France v Ireland on February 9th and Ireland v Scotland two weeks later. Wayne Barnes followed by Nigel Owens will take his place in those fixtures.