It is nice to be nice, but Joe Schmidt was struggling.

Running the rule over Scotland, the Ireland coach had heaped praise on the sharpness of Stuart Hogg at full-back and Sean Maitland on the wing, on the craft of the midfield backs and the cleverness of Greig Laidlaw at scrum-half. He said the back row were rich in talent and the second row had power and athleticism. And then he hesitated.

As well he might. For if the news that Euan Murray had injured his hand chopping wood at a Worcester Warriors barbecue (now officially the least successful team-building event in rugby history) did not deepen Scotland's front-row woes - Murray would not have been available for next Sunday's Six Nations clash with Ireland anyway - it had certainly thrown them into sharp relief.

The likelihood is that Scotland will go into the game with Moray Low in Murray's tighthead position. No worries there, for the Glasgow prop put in decent shifts against South Africa and Australia in November, but things become alarming after that. Geoff Cross, the back-up tighthead, has started precisely one competitive match this season. Although fit, his combined RaboDirect PRO12 game time for Edinburgh adds up to just 65 minutes.

This is not to denigrate Cross, rather to highlight the structural weakness in Scotland's rugby hinterland. Willem Nel has been playing well at tighthead for Edinburgh, so Cross cannot get a look-in at the club, but next Sunday he will almost certainly have to do a shift for his country.

"We've got to find out about them," said Scotland coach Scott Johnson of Cross and Low. As both have been on the international scene for the past five years and have clocked up a combined total of 46 Test appearances, you wonder just how much finding out there is left to be done, but Johnson presumably has something in mind.

"Not everyone is blessed with a depth at tighthead prop," he said more candidly. "We're just going to have to weather that one."

And the rest. Johnson managed to widen his pool of experienced international players last year, handing out caps like confetti on the summer tour to South Africa, but it would be pushing it to say that any of the newcomers made a huge impact or immediately established themselves as clear front-runners for their respective positions. Tim Swinson was probably the best of the crop, but he is still below Jim Hamilton and Richie Gray - as, in a literal sense, most people are - in the second-row pecking order.

Moreover, Cross is far from being the only player who looks a little under cooked at the moment. Jonny Gray and Matt Scott have both been out of action since the autumn Tests, yet both were named in the Six Nations squad. Gray has since been named as captain of the Scotland A team that will take on the England Saxons at Scotstoun on Friday evening, but the indications are that Johnson could still be pitching Scott straight in after almost three months without a competitive game.

"I would not put him on if I felt there was any doubt about his ability to go the distance," Johnson said. A fine principle, but as it was a hand injury that Scott suffered, fatigue is unlikely to be a burning issue.

Johnson has been trumpeting Scott's case for some time. "Matt is going to be a prodigious talent as an international rugby player," the coach said last week. He has cover in the shape of Duncan Taylor, and there are various possible midfield permutations involving Taylor, Sean Lamont, Alex Dunbar and Nick De Luca, but it is clear that Johnson wants Scott back in the No 12 shirt as soon as it can be arranged.

His anxiety on that front is understand- able given the perennial problem of fly-half. Johnson's mantra of the moment is that Scotland need to be consistent, and it is in the No 10 slot that the quality has been most desperately missed in recent years. It is a rugby fundamental that a successful side need a playmaker who is a bolt-on selection, but neither Ruaridh Jackson nor Duncan Weir has managed to become that at Glasgow, let alone Scotland. Given the success of Greig Tonks' recent conversion from full-back to fly-half, it is not impossible that Johnson will start to think of doing something similar with Scott.

And there is, of course, the Johnson factor itself. Most coaches go into the Six Nations hoping they don't get the bullet at the end of it; Johnson goes in with the reassurance of knowing that he has already secured promotion to the director of rugby role he will assume at Murrayfield at the end of the tournament, when he hands on the head coach responsibilities to Vern Cotter. Will the players want to send him on his way with the gold watch of a successful campaign? Or will they think of him as a dead man walking, his influence already on the wane?

Bad news if they do. "I will still be involved," Johnson told journalists recently. "I will still be coaching with Vern. Everyone has got that slightly wrong. It's not about me. I love coaching blokes and I love being involved in the team, and that's what I'll continue to do. Nothing really changes. The only difference is that you won't have to put up with me and I won't have to put up with you.

"I took the job because I still want to do bits of it. I still want to be part of the team. I think back to when I started and where I grew up, so to be here, in the biggest tournament in the world, well if you're not excited then you shouldn't be here. I feel privileged to do it and whether it is my first or last I would feel the same. It is just a great tournament to be involved in. It is a great way to live life."