Mateta's contract with Crystal Palace is due to expire at the end of this season, but he has disputed whether the 12-month extension of his contract was valid. He took the case to an independent tribunal under Premier League regulations last season, but lost. Fifa also rejected his claim after ruling it did not have jurisdiction over the dispute. The outcome of the tribunal has not been disclosed, but Crystal Palace insist Mateta's contract remains binding.
Mateta has been trying to force through a move from Selhurst Park for some time and it is understood he has interest from Aston Villa, who are considering whether to sell Ollie Watkins to the Saudi Arabian side Al-Hilal. The French striker played in Crystal Palace's defeat at Everton on Saturday, but his future at the club remains uncertain.