Ireland prop Mike Ross has been ruled out for at least six weeks with a hamstring injury, putting his participation in the Six Nations opener against Wales in doubt.

The 36-year-old sustained the serious tear during Leinster's Champions Cup defeat at the hands of Toulon on Saturday, with subsequent scans confirming the extent of the injury.

Ireland are due to begin the defence of their Six Nations crown at the Aviva Stadium on Sunday, February 7, leaving Ross in a race against time to prove his fitness.

Ross made his Six Nations debut against Italy in February 2011 and has since started every single one of Ireland's matches in the tournament.

Head coach Joe Schmidt could have a number of absentees for the opener, with current doubts over the fitness of Johnny Sexton, Tommy Bowe, Peter O'Mahony and Iain Henderson, in addition to the lack of stalwart Paul O'Connell following his retirement.