Sheffield United have scored a major breakthrough in their battle to ensure Kean Bryan, the former Manchester City defender, is fit and available for selection.
Bryan, who is yet to make a senior appearance since arriving at Bramall Lane before August's transfer deadline, suffered the latest in a series of injury set-backs during a Professional Development League fixture earlier this month.
The game, against Hull City, had been expected to mark the final stage in the youngster's rehabilitation following illness and a minor muscle complaint. But United's medical staff were concerned when Bryan was forced to be withdrawn at half-time after complaining of discomfort at the back of a leg.
The subsequent investigation, Chris Wilder has confirmed, revealed the source of the problem.
"There was some scar tissue still on one of his hamstrings," the United manager said. "So we've been able to sort that out and Kean has been back out there on the grass again.
"Everything had been done correctly. Nothing showed up and he'd passed all the tests he had to during training, so that's when we put him in the game.
"But he had to stretch for something during it, probably overstretched a bit, and couldn't carry on. That's when he felt it.
"Initially, it was a bit of a mystery because, as I say, he'd gone through everything he had to. But we know what it was now and so it's been sorted."
Bryan, aged 21, agreed a three year contract with United after leaving the Premier League champions. Despite failing to make the breakthrough in Manchester, it is a measure of how highly officials at the Etihad Stadium rated him that they insisted on inserting a sell-on clause into the deal which took Bryan to South Yorkshire.
With another summer signing, former Huddersfield Town defender Martin Cranie, recently completing a truncated 'pre-season' programme, Wilder believes Bryan's presence, combined with Jake Wright's progress in recent weeks, means United's rearguard will be equipped to cope with the rigors of the Christmas schedule.
Like Bryan, Wright has yet to feature this term after fracturing a cheekbone during July's friendly against Stocksbridge Park Steels and later being diagnosed with a back problem.
"Jake is back out there too," Wilder said. "He's been working with Kean and the rest of them. He's on the grass as well, so that's good news. They're coming on well."