West Ham United have 'vigorously denied' that they have breached FIFA rules following Diafra Sakho's withdrawal from the Africa Cup of Nations.
World football's governing body has opened disciplinary proceedings for a "potential violation" of their regulations.
Sakho withdrew from the Senegal squad with a back injury, but he played for West Ham two weeks later during their victory over Bristol City in the FA Cup.
While FIFA forbids any player from playing for their club when they should be turning out for their country, West Ham have insisted that they have not breached any rules.
"Diafra Sakho and West Ham United vigorously deny that they have acted in breach of FIFA regulations," read an official statement from the Premier League club. "They regard the proceedings as clearly unfounded and are requesting their dismissal."
West Ham boss Sam Allardyce recently revealed that he was advised not play Sakho during Saturday's 2-0 defeat at Liverpool.