Ireland fly-half Jonathan Sexton has been ruled out for up to six weeks with a foot injury - casting doubt over his participation in the British and Irish Lions tour to Australia this summer.

Sexton damaged a tendon in his left foot at the end of training yesterday, resulting in his withdrawal from the starting XV for tomorrow's RBS 6 Nations clash with Italy at the Stadio Olimpico.

The 27-year-old had only just recovered from the hamstring injury he sustained against England on 10 February and now faces an even longer spell on the sidelines.

"We were told yesterday that Jonny will be out for four six to weeks," Ireland coach Anthony Foley said.