In a statement this morning the SRU said: "The Glasgow Warriors forward sustained knee ligament damage in the national team's round two defeat to Ireland at BT Murrayfield Stadium on Saturday and will return to the care of his club's medical team".
"In that first half we were in our 22 for 34 per cent of the time and in our half for about 72 per cent of the time". It's frustrating as you love going up against the best teams in the world, and we get close, but come up just short.
Conor Murray, Jacob Stockdale and Keith Earls bagged Ireland's tries, while Finn Russell's interception provided Scotland's try for centre Sam Johnson.
The New Zealand-born fly-half - who moved to Munster previous year after being an understudy to Sexton at Leinster - made a nervy start with his pass being intercepted leading to Scotland's try at the end of the first-half.
Scotland badly needed some points but turned down a simple three for a quick tap by Russell and the Irish defence swarmed to force a turnover inside their own five metre line.
First blood went to the hosts via a Greig Laidlaw penalty.
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Aguero had a simple task to make it 3-0 six minutes later when he pounced on Ross Barkley's slack header towards his own goal. Sergio Aguero scored twice while Raheem Sterling and Ilkay Gundogan also found the net as the visitors sank without a trace.
"We'll go back to the pressure we put on and the coaches put on us. Both of the teams" energy levels dropped in the second half because of the effort that they put into the first half.
"They were well organised in defence and we knew how unsafe they would be in attack". 'If we were able to replicate it in the second, I think we'd be here with a win.' Laidlaw, meanwhile, was critical of referee Poite, citing one instance of particular injustice as far as the Scotland captain was concerned. "We've got a lot of improving to do".
But a key period just before half-time saw Ireland heroically and desperately hold off a Scottish attack that lasted 25 phases.
Scotland return to Six Nations action on February 23. when they travel to Paris to face France. Star fullback Stuart Hogg was hit late by Peter O'Mahony, flew over the Irish flanker, and crashed onto his right shoulder. We'll see what will happen over the next couple of days.
The 36-year-old hooker - who along with his team-mates put in a considerably better performances than in the 32-20 defeat by the English in Dublin - said it had been a challenging week but they had come through.