Ireland and Leinster have been hit with a major blow after centre Garry Ringrose was ruled out of action for six weeks with an ankle injury.

On a more positive note, having failed a head injury assessment against Ulster, Tadhg Furlong has passed the third stage of the return to play protocols and is in line to return for Saturday's Champions Cup clash with Glasgow.

While recent absentees Sean O'Brien, Joey Carbery and James Ryan have a chance of facing the Scots on Sunday, Leo Cullen will be without hooker James Tracy for up to five weeks. The front-row forward dislocated his elbow against Ulster.

Leinster confirmed to RTÉ Sport that 22-year-old Ringrose is facing a spell on the sidelines which will see him miss the Champions Cup games with Glasgow and Montpelier, as well as his country's opening Six Nations fixtures in February, against France and Italy.

Ringrose picked up the injury in Leinster's Pro14's defeat of Ulster at the RDS on Saturday.

It's a hugely frustrating setback for the Dubliner, who had shoulder surgery back in July.

He returned to action at the start of December against Treviso and had been slowly regaining his sharpness over the last month.

He now must endure another period of rehab, with the Six Nations just three and a half weeks away.

Joe Schmidt's men begin the tournament in Paris.

Listen to live and exclusive radio commentary of Ulster v La Rochelle (Saturday 1pm) and Racing v Munster (Sunday 3.15pm) on RTÉ Radio 1.