Ireland captain Caelan Doris is in a race against time to be fit for the Nations Championship after surgery set back his recovery beyond initial expectations. The number eight will miss Leinster's Round Two URC clash against the Sharks, with head coach Leo Cullen unable to confirm when he will return.

"He won't be playing for us in this period, so in and around November or beyond," Cullen told the Irish Times. "I don't know. I'm not trying to be smart here. I'm not 100 percent sure yet."

Doris, 27, first suffered a foot injury during Leinster's URC final win over the Bulls, which ruled him out of Ireland's southern hemisphere leg against Australia and New Zealand. He subsequently underwent a knee procedure, and his recovery from surgery has now pushed out further than Cullen originally anticipated.

"He had surgery and originally I thought he would play for us in this first block of the season, but I think that's just been pushed out of the loop itself. Exactly how far, I'm not sure," Cullen said.

Ireland face Fiji, Argentina and South Africa in their November Nations Championship campaign, with Cullen unable to give any assurance that his captain will be available for any of those fixtures.