The future of Atletico Madrid forward Antoine Griezmann remains in the balance following the club's rejected appeal against a transfer ban

Atletico Madrid have had their appeal against their transfer ban rejected by the Court of Arbitration for Sport (CAS).

Atletico, who have said the ban "causes an irreparable damage", will be unable to make any signings until January 2018.

The judgement could also possibly affect a potential move away from Atletico for Manchester United target Antoine Griezmann, whose current contract contains an £87m buyout clause.

The Spanish club were banned from making signings for two transfer windows, along with city rivals Real Madrid, by FIFA last year after breaching rules over the transfer of foreign players under the age of 18. They were also hit with a £622,000 fine.

CAS have since reduced Real's suspension by a year on appeal, but have decided not to rule in a similar style, leaving Atletico with little choice other than to shelve their summer transfer plans.

Atletico boss Diego Simeone will be unable to sign players this summer

A deal had already been agreed to sign Alexandre Lacazette from Lyon, though a move to bring the France forward to Madrid will either need to be put on hold until January or cancelled altogether.

An Atletico statement read: "After the Court of Arbitration for Sport (CAS) has dismissed the appeal presented by Atletico Madrid against the penalty imposed by FIFA's Disciplinary Committee on the case of registering players under age and that was ratified by FIFA's Appeal Committee, reducing the financial penalty, but maintaining the prohibition of registering licenses in the next transfer market period, our club wishes to state the following:

"We consider that the decision to support the prohibition of registering players in a second period, corresponding to the summer of 2017, supposes a comparative disadvantage and discriminatory treatment to our entity, since recently and in a similar case, the penalty was partially lifted, allowing to register players starting on July 1. This ruling is unfair and causes an irreparable damage to our club.

"The resolution has been communicated after the time limit established in the agreement signed by the parts, which finished yesterday, May 31, 2017. This shows a lack of respect for our institution.

"We want to reiterate that we have been penalised despite strictly complying with the Spanish legislation, as we have always processed all our licenses with Madrid's Football Federation, as the Sports Law indicates.

Alexandre Lacazette had been set to join Atletico in the summer

"Our sports planning for next season has contemplated at all times the two scenarios that could arise once CAS announced their decision. From this moment on, the club will move forward in the negotiations necessary to formalise the operations to register players from January 1, when we will be authorised by FIFA to register new licenses.

"We have full confidence in our current squad, with which we have won direct passage to the Champions League for the fifth year in a row and have reached the semi-finals of the Champions League and the King's Cup.

"The club has the commitment of the players and coaching staff to continue competing at the same level next season, despite this decision that is evidently detrimental to us. Together, team, club and supporters, we will continue to fight for our goals."

Sky Sports News HQ understands United are interested in signing Griezmann, with manager Jose Mourinho targeting four major signings.

Following the ruling from CAS, Atletico are likely to be keen to keep hold of the France international, although they will be unable to stand in his way if his release clause is met.

The forward recently revealed on French TV that his chances of a switch to Old Trafford were "six out of 10", but has since dismissed reports that a deal is already in place for him to join United.

"All the rumours are unfounded," Griezmann tweeted from his official Twitter account. "I'm still Colchonero. My direction will be established after discussion with my sporting advisor."