The Premier League said all rules were followed in Chelsea's signing of Traore on January 1, 2014, the first day of the transfer window opening following his 18th birthday, on September 6, 2013.
What prompts questions is the earlier recruitment of Traore and his participation in a Chelsea under-18s match at Arsenal on October 23, 2011, when he was 16.
The Press Association has a photograph of Traore taking part in the game at the Emirates Stadium