Striker Diafra Sakho and Premier League club West Ham United face a FIFA inquiry over Sakho’s withdrawal from Senegal’s Africa Cup of Nations team.
According to football’s governing body, it has opened disciplinary proceedings for "a potential violation of regulations", reports bbc.com.
The 25-year-old pulled out of the squad citing a back injury, but later scored for United in their 1-0 FA Cup triumph over Bristol City Jan 25.
FIFA rules state that a player cannot appear for a club if he was meant to be on international duty, but the Hammers deny any such wrongdoing.
A FIFA spokesman said: "We can confirm that disciplinary proceedings were initiated against the player Diafra Sakho and the club West Ham United for a potential violation of the Fifa regulations on the status and transfer of players."