Zander Diamond's move from Aberdeen to Hearts has been held up after a medical highlighted an ankle injury.
The Tynecastle club will seek a second opinion but BBC Scotland believes the out-of-contract defender is still likely to make the switch.
Diamond, 25, is thought to have sustained the injury two years ago.
The centre-half came through the Dons youth team and has been a first-team regular for eight seasons, but manager Jim Jefferies wants him at Tynecastle.
Jefferies told BBC Scotland last Wednesday that he hoped to secure Diamond's signature and help to make the most of the player's talents.
"Zander is one that way back came on to the scene at Aberdeen and did fantastically well," he said.
"He has lost his way over the past couple of seasons. Maybe he has been at Aberdeen too long. Can we get that player we feel is in there out of him?"
The Hearts boss views him as a player who could strengthen the Hearts back line, given the right coaching and pairing.
"He has hardly played with a regular, experienced centre-back," Jefferies told BBC Radio Scotland's Sportsound.
"I have said to him face to face that he has a lot of faults but he has a lot of pluses as well.
"I have done the homework, I have spoken to a lot of people who have worked with him. They say he is a terrific lad to work with and great in the dressing room. He is a great competitor.
"People like Andy Webster, how he brought on Garry Kenneth at Dundee United, he could do the same job here [with Diamond].
"I had the same problem with Steven Pressley when he first came to the club. People were questioning that and we all know how well he turned out."
Last week, Hearts added Kilmarnock midfielder Jamie Hamill, Motherwell striker John Sutton and St Johnstone defender Danny Grainger to their squad for next season.
And if the move for Diamond can be sorted out, it is unlikely that he will be the last player to join the Gorgie side this summer.
"We are still after a couple more if we can manage it. We are looking at one or two that I will be putting to Mr Romanov when we meet up soon," said Jefferies, who will assemble his squad for the new campaign on 22 June.
"Going into Europe you need a decent squad. If you get into the group stages it's something you need to deal with. These boys coming in will make us stronger.
"It's nice to get them tied up early so they can go away in the summer and relax.
"You want them there for pre-season training. They have piece of mind now and they all look forward to the challenge of playing at Hearts."
Meanwhile, on their way out of Tynecastle are Polish defender Dawid Kucharski, 21-year-old midfielder Paul Mulrooney and striker Jamie Mole, who has spent the last few seasons on loan to clubs in the First Division.
None of the players has been offered a new contract.