DUBLIN (Reuters) - Ireland flyhalf Jonathan Sexton has been ruled out of Ireland's side for their final Six Nations match against Italy on Saturday hours after being named in the starting line-up earlier on Thursday.

After missing the last three games with a hamstring injury, Sexton was in line to resume his kicking duties in place of Paddy Jackson, but tore a tendon in his left foot in training.

Ireland's Jonathan Sexton celebrates after scoring a try against Argentina in the international rugby union match at the Aviva Stadium in Dublin November 24, 2012. REUTERS/Cathal McNaughton

Jackson will now come in from the bench for his third cap, with Ian Madigan, who made his debut against France last weekend, coming on to the replacements' bench.

Coach Declan Kidney omitted veteran second row Donncha O'Callaghan in favour of Leinster's Devin Toner.

Ulster wing Craig Gilroy returns in place of Fergus McFadden who suffered a rib injury in last weekend's draw against France.

Ireland:

15-Rob Kearney, 14-Craig Gilroy, 13-Brian O'Driscoll, 12-Luke Marshall, 11-Keith Earls, 10-Paddy Jackson, 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, 19-Devin Toner, 20-Iain Henderson, 21-Paul Marshall, 22-Ian Madigan, 23-Luke Fitzgerald.

(Reporting by Stephen Mangan; Editing by Clare Fallon)

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