Preparations for Scotland’s tour of Argentina have been hit by another specialist withdrawing, but there was also good news for Frank Hadden, the head coach, yesterday with signs of matters easing in the lock crisis that had been a major headache for him.

His problems yesterday began with Craig Smith, the tighthead, pulling out of the trip. He was there only as a replacement for Moray Low, his Glasgow rival, and now Hadden has called in Geoff Cross, Smith’s Edinburgh colleague, who becomes the fourth specialist tighthead to be called into the squad, where he will probably be the back-up to Euan Murray.

Smith simply felt that, after a second season ruined by injury, he was not in the right frame of mind to tackle another tough tour, particularly one that puts real pressure on the props against an Argentina side who pride themselves on their scrummaging. He is so disenchanted with the seemingly nonstop run of injuries, including a persistent calf-muscle problem that has flared up twice this year, that he has yet to decide whether he will return to professional rugby next season.

“I was not happy going if I could not give it everything,” he said yesterday. “I did not want to go and then have a detrimental effect on the squad. I feel like I’ve been going pretty much nonstop for eight years and I’ve lost a bit of hunger, a bit of zest for the game.

“It is as much the mental side as the physical side. I just want to get reinvigorated and get my oomph back again for next season.”

On the plus side, Alastair Kellock and Craig Hamilton, the two locks who have been recovering from injuries, both completed both the training sessions yesterday, including hard scrummaging and lineout work. Assuming that neither suffers an adverse reaction, they will be available for selection for the tour and could fill the two remaining spaces among the forwards.

Whether they both go to Argentina or whether one is siphoned off to the A team trip to the Churchill Cup in Canada and the United States depends on events in France, where Scott Murray, Scotland’s most capped player, is based.

“I have been in regular contact with him at Montauban,” Hadden said yesterday. “The information he had was that his club would be prepared to release him if they won this coming weekend. We still have to decide if we can accept that, since it means he would be late joining us.

“We also have to decide whether the club would stand by that if they did win - I don’t know that. We would have to monitor it.

“His experience would be invaluable, though. That’s why I have gone to the lengths I have, speaking to him on a weekly basis and he has been speaking to his coaches on a weekly basis, getting clarification on the situation.

“There was a possibility that he might have joined us this week, but the club have moved it on a week, as is within their rights.”

Montauban are out of the running for the French Championship but, with three games left, need one more win to be certain of Heineken Cup rugby next season. They are not prepared to risk their ambition of joining the European elite by releasing Murray for Scotland duty before they have sealed their place.

They host Clermont Auvergne this weekend but the cause of Murray and Hadden is not lost since the runaway league leaders, who have already wrapped up a play-off place, may not be interested in going eyeballs out at a notoriously tough ground.

As for Cross, he was delighted at his unexpected elevation to the national squad. Little more than a month ago he was struggling to get games for Edinburgh but cemented a starting spot during the successful end-of-season run and is reaping the rewards.

“It was certainly not what I was expecting,” he said. “I was preparing to go on the A tour to Canada and then in a less-than 30-second interview with Frank [Hadden] learnt I was going to Argentina instead. It is a fantastic opportunity that I am very excited about.

“We had an Argentine player at Edinburgh this season [Augusto Allori] and speaking to him and looking at the analysis we have done, it seems they play at a very high pace but match that with a high physicality, and I am relishing the physical challenge that is coming. The important thing for me is to keep doing what I have being doing, the things that got me here and gave me this chance.”