Marseille's Senegalese striker Bamba Dieng failed a medical at Ligue 1 rivals Nice late on transfer deadline day on Thursday, a source close to the deal confirmed to AFP, hours after he had seemed set to sign for Leeds United in the Premier League.
Dieng, 22, appeared to be on his way to England to sign for Leeds earlier on Thursday, with the English side's chairman, Andrea Radrizzani, taking to Twitter to suggest a deal had been done while they also tried to sign PSV Eindhoven forward Cody Gakpo.
"Let's welcome Bamba Dieng and we will continue to work on Gakpo," he said.
Yet in the meantime Nice intervened in an attempt to take Dieng along France's Mediterranean coast, with Radrizzani later admitting: "Part of the madness of deadline day. We have been screwed up. It happens even to the best ones."
Dieng was then on the verge of signing a five-year contract at Nice with Marseille set to receive a transfer fee of nine million euros plus an extra one million euros in potential bonuses, a source told AFP.
However, local newspaper Nice-Matin reported that a problem with Dieng's medical had held up the deal.
"There was a minor problem with the medical," the source confirmed, adding that "the transfer is not off" despite the deadline passing in France.
Marseille had been eager to offload the Africa Cup of Nations winner in an attempt to raise much-needed funds, despite Dieng enjoying an impressive breakthrough campaign last season.
Also on Thursday, Marseille sold Croatian international defender Duje Caleta-Car to Premier League side Southampton, while bringing Moroccan playmaker Amine Harit back on loan from Schalke for a second season.