Under-23s midfielder Conor Grant has seen a proposed loan move to Plymouth Argyle fall through due to an oversight by Everton.
Grant was due to make the temporary switch to the southwest last week, with Argyle manager Derek Adams expecting him to be available for their match against Oldham.
It was discovered that Grant is ineligible to play for Plymouth, having already turned out of Crewe Alexandra, where he was on loan earlier this season, and Everton's U23s side.
FIFA rules prohibit players from representing more than two clubs per season and, after making 18 appearances for Crewe and playing a solitary game for the Blues in the Checkatrade Trophy in August against Notts County (despite being an U23s fixture, it counted under FIFA rules as a first-team match because of the Football League opposition), Grant cannot join a third team.
Adams admitted Plymouth's role in the mix-up but was critical of Everton's mistake which deprived him of a player he was hoping to sign.
“It was an oversight and the football management team have got to take full responsibility," Adams said. “Ourselves and Everton. They obviously knew he had played in the Checkatrade Trophy and had been out on loan.
“We knew the rules, but we didn't know he had played that one game in the Checkatrade Trophy.”
Grant, 22, is out of contract at Everton in the summer.