Johnny Sexton is out of Ireland’s opening Six Nations match against Scotland in Murrayfield with a calf strain. The Irish outhalf picked up the injury on Monday and management have decided not to risk any further damage by pushing him into training this week.

Coach Simon Easterby could not say when Sexton would be available again. Munster’s Peter O’Mahony and Ulster winger Andrew Trimble are also struggling with injury, with O’Mahony also ruled out of any role in Ireland’s opening match.

“The update (on Sexton) is he ran yesterday afternoon and just felt a little bit of tightness in his calf,” said Easterby. “We believe it right not to push him through the week and risk potential further damage.

“So he won’t be available this weekend. He’s obviously had a number of lower limb injuries, one hamstring which we have managed along with Leinster through the Christmas period after the Autumn.

“We redressed the balance there in terms of the hamstring. He picked up a calf in the Castres game. He only managed 20 minutes in that game. He had to come off.”

While Ireland are hopeful that he will quickly recover from the injury, Easterby said they are not going to rush Sexton back or even put a timescale on his rehabilitation.

“As a result of that little calf strain he’s got we don’t want to compromise his calf any further,” added Easterby. We felt it best to leave him out this week and make sure that he is right for the upcoming games.

“It’s purely now that we manage his return to full training. That will take as long as it takes. We’ve no time scale on that. He just felt tightness yesterday and we felt it was in the best interest of Johnny that he didn’t try and push into today and further into the week.”

When pressed on the issue of how long Sexton would be on the sideline, Easterby was non committal.

“I couldn’t say. It’s a case of monitoring and managing him for the rest of this week and get to next week and reassess where he is at that point.”

The same will apply to Peter O’Mahony who has had a scan for a groin injury.

“They (O’Mahony and Trimble) both picked up a little bit of tightness yesterday, Pete in his hamstring and Andrew in his groin,” explained Easterby. “Andrew did do some running today but on the side pitch. Peter has a scan this afternoon that will hopefully give us an indication for the reason for that tightness.”

The Sexton injury means Ireland will be light on backup in the outhalf position. For the match day squad it will be two players from Paddy Jackson, Ian Keatley and Rory Scannell. Bordeaux’s Ian Madigan was not considered despite Keatley and Scannell’s relative inexperience at international level.

“Well, if there are only three tens in the squad then the chances are that two of those three – Paddy, Ian Keatley and Rory Scannell – will be on the bench or starting,” said Easterby. “What is the alternative?”

Easterby explained that Madigan’s unavailability because he was tied to his club has made it difficult for Joe Schmidt to consider him for a role in the Irish team despite the current difficulties.

Last week he was on the bench for his club’s game against Clermont and was not available to Ireland.

“Unfortunately he couldn’t be with us last week anyway because he was on the bench for Bordeaux against Clermont so it compromises his position with us when he is not playing in Ireland and we are trying to support those guys who are staying here,” said Easterby.

“Circumstances may allow us to look outside of that but as it happens at the moment we have got those three guys in and Mads hasn’t been selected in the squad. He couldn’t be included last week so that hasn’t really helped his cause.”

While the Irish management have clear intentions to support the home based players above those playing outside Ireland, they have not ruled out a role for the former Leinster outhalf further down the road.

“It is based on last week and on the fact that he couldn’t be with us,” said Easterby. “He played some part in Bordeaux’s game against Clermont and, moving forward, it is case by case but we want to try and support those guys who are playing their rugby in Ireland.

“There will potentially be exceptions to that rule but as it happens at the moment this is the case and there isn’t any issue in terms of us looking at Mads in the future.”