Nantes snapped Augustin up after he was left without a club, with Leeds and RB Leipzig involved in a dispute.
Leeds had been expected by RB Leipzig to sign Augustin on a permanent basis at the end of a loan spell, but the Whites dispute the German side’s view and the matter is now set to be solved in the courts.
Augustin has been trying to rekindle his career in France, but so far he has struggled to make an impact at Nantes and was sent to train with the reserve team last week due to a lack of sharpness.
Nantes have been determined to find out the source of Augustin’s struggles and the club have now confirmed a medical examination has shown that the striker is suffering from the effects of Long Covid.
Augustin was infected with Covid-19 and is still feeling the effects.
Nantes said in a statement: “The player will now pursue a strict medical protocol, adapted to his current state of health, necessary to recover all of his means and his physical form.”
As Augustin bids to recover, he is due to continue to train with the reserves.
“At the same time, as part of a re-athletic programme of several weeks, determined by the doctors and the club, he will remain at the disposal of the reserves until the end of the season.
“Due to medical confidentiality, no other information will be communicated about the situation of Jean-Kevin Augustin.”
The news is a further blow to Augustin, who had looked set to ply his trade in the Premier League at Leeds this season, but is instead battling to recover from the effects of Covid-19 and put his career back on track.
Leeds could still be forced to pay €21m to RB Leipzig for Augustin.