Grant Hanley's fitness is a concern for Scotland, who have been left sweating about the Norwich City captain's availability for this summer's Euros.
Hanley formally withdrew from their squad ahead of friendlies against Northern Ireland and the Netherlands over this international break after David Wagner expressed his concern over a loss of sharpness.
The 32-year-old has just returned from a long-term Achilles issue but missed City's trip to Stoke at the weekend and has been pulled out of team training altogether to work on a new individualised conditioning programme.
That has led Hanley to withdraw from Scotland duty, and assistant John Carver expressed worry about his condition when quizzed after Tuesday's press conference.
"It is a concern because he's one of our squad," said Carver to Sky Sports. "But it's up to Grant to get fit again and make sure he's okay.
"That's one of the reasons he's stayed behind to work with the people at Norwich. It's important he's in good condition.
"If he gets himself fit and starts playing again, there's no reason why he can't get back into this squad."
City duo Kenny McLean and Angus Gunn have joined up with the Scotland squad and will be hoping to cement their place in Steve Clarke's squad ahead of this summer's championships.
Gunn has returned to the fold after missing the last set of internationals through injury and will have more competition on his hands after four goalkeepers were selected ahead of the games this month.
That is owing to the return of veteran keeper Craig Gordon after a long-term injury, and Carver is already seeing the benefits of increased competition between Scotland's shot-stoppers.
"That will be down to Steve and who he selects but what it [having four goalkeepers] has added is a huge amount of competitiveness," Carver said.
"We saw that yesterday [Monday] in training because every single one of them was right on it.
"Normally the first day they ease their way in but we had a small-sided game towards the end of training and the four goalkeepers were outstanding."
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