Paul O'Connell is set to be out for up to eight months as he recovers from the hamstring injury that ruled him out of the World Cup.
The Ireland second row called time on his international career when he tore his hamstring during a pool victory over France, missing the quarter-final loss to Argentina.
He signed a deal with European champions Toulon for this season, and will head to the south of France in December to continue his rehab.
Having undergone surgery, O'Connell expects to be absent from four to eight months, with the latter effectively ruling him out for the season at his new club.
"I don’t know, it’s very approximate," said O’Connell to the42.ie at the launch of the PINERGYsmart service. "It’s kind of between four and it could be eight months. You just don’t know.
"The surgeon was very happy with how the surgery went. He doesn’t see there being any problems, but I’ve had a lot of injuries that haven’t really gone like that. There’s been ups and downs with my injuries in terms of how I’ve recovered.
"I wouldn’t be as naive to think that it’ll be plain sailing. I’m just going to follow the protocols religiously, as I’ve always done, and hopefully that can get me in a place to get back playing before the end of the season.
"I was operated on on the Thursday and I’ve just been on the flat of my back since," added O’Connell.
"I got out of the hotel to go to the Argentina game, then we travelled home and I’ve literally just been on the flat of my back for the last two weeks.
"I was pain free after about a week on the flat of my back. I’m pain free sitting down now for about four days. The Munster lads took me out for lunch twice and Emily (his wife) took me for a pizza once, but apart from that I haven’t left the house. This has been my first time leaving the house.
"It’s a frustrating time. I spoke to the physio in Toulon last week and he said it’s an injury where you just have to do your time with it. Shoulder injuries or even cruciates now, you come out of it and there’s a lot you can do straight away.
"With this one you really have to put down a really tough six weeks where you have to be very careful, particularly in the first two weeks."