The Whites confirmed the appointment of Gracia as their new manager on Tuesday, more than two weeks after Jesse Marsch was sacked.
Leeds have been hoping to have the former Watford boss in the dugout against Southampton on Saturday but that is now uncertain.
The club are yet to secure a work permit for the Spaniard for him to start work in England.
Despite being at Watford before, Gracia does not qualify for an automatic work permit due to new regulations following Brexit.
He cannot even take training with the Leeds first-team squad until the paperwork for his visa is sorted out.
His work permit will have to be approved by a special panel and he must be granted a governing body endorsement (GBE) by the FA.
There is now serious uncertainty over whether Gracia will be in the Elland Road dugout when Leeds take on Southampton this weekend.
