Johnny Sexton is set to be fit for Ireland's opening Six Nations match against Wales in Cardiff on Sunday week.
The captain picked up a hamstring strain in Leinster's win over Munster last weekend, but he is hoping to train either later this week or early next week.
Ireland finished third in the 2020 Championship, defeating Wales by 10 points in Dublin.
Speaking at the tournament launch today, Wales coach Wayne Pivac says Andy Farrell's men will be a tough nut to crack.
"Certainly playing Ireland in game one is a big game for us. Obviously, with what happened in the last tournament, they were there right to the last weekend. We have got a lot of respect for them and it's a game that can set the tone for us for the rest of the tournament. It's a fast start we're after, we're wanting to get a good performance on the park and making sure that instead of having patches in games, we are being consistent across the 80 minutes and that's certainly what we'll be looking for."
Ireland haven't won at the Principality Stadium in the Six Nations since 2013, and Pivac knows the lack of supporters could neutralize any advantage Wales might have.
"It is a different occasion. You can't hide away from that. It is not the same enjoyment level in terms of having that sea of faces and sea of red and the singing and the support that we get. It is definitely a 16th man so to speak. That's out the window and it's the same for everybody, so it's making sure we prepare the best we can and learn from the last campaign without fans."
Captain Alun Wyn Jones agrees that it's an intense Celtic clash when Ireland come to town.
"It stands out for a lot of people because obviously, the games we've had have potentially made the difference to championships. From a Welsh perspective, we are acutely aware of being in the Pro 14 and the domestic success that the likes of some of the Irish provinces have had and it's inevitably carried over into the international window. To have them first out - whether you are Irish or Welsh is a mouthwatering one to see what's going to happen."
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