Fifa has intervened over the row between Everton and South Africa about Steven Pienaar's call-up date to the African Cup of Nations.
Toffees boss David Moyes spoke on Monday explaining that he planned to keep the midfielder for Tuesday's Carling Cup semi-final against Chelsea.
Moyes argued to the South African Football Association that the 14-day rule states that a country can claim their player 14 days before international action.
The African Cup of Nations begins on 20th January, but South Africa are not in action until 23rd January - which is 15 days after the game at Stamford Bridge.
However, Everton have been instructed to release Pienaar for international duty with South Africa immediately.
Fifa has clarified that the 14-day rule applies from the start date of the tournament, not when the country plays its first game of the tournament.
An Everton spokesperson said: "Steven will be going to London today, but not to Stamford Bridge. He will be flying out from Heathrow.
"We have been contacted by Fifa and told he has to be released by us ahead of the Chelsea match."
Everton secretary David Harrison added on the club's official website: "We are extremely disappointed that a common-sense attitude has not been shown, as has been the case with a number of other federations.
"Despite Fifa's attempts to clarify the regulation, we do feel - as do a number of other European clubs - that there is a distinct grey area on this ruling and we are extremely disappointed that this has only been made clear at this late stage."