FIFA have told Chelsea they cannot recall any players on season-long loans under the terms of their transfer ban.
It is another body blow for the English club who were banned from signing any new players during the next two transfer windows when FIFA found them guilty of inducing teenager Gael Kakuta to breach his contract with Lens two years ago.
Although the Blues intend to appeal against the punishment, coach Carlo Ancelotti was hoping to minimise the damage by recalling England Under-21 defender Michael Mancienne from Wolves, forward Scott Sinclair from Wigan Athletic and Argentinian striker Franco di Santo from Blackburn Rovers.
Di Santo can return, as his agreement was only for half the season. But Sinclair's was for the full season and in Mancienne's case, FIFA will have to rule on whether an "emergency release clause" can be applied.
"If it's a season-long loan, it cannot be terminated in order to bring players back," said a FIFA spokesman.
The club expect to hear from the sport's world governing body in the next 10 days with their full reasoning behind the transfer ban.
The Blues then have 21 days to respond. Should their appeal fail, and further injuries occur in the next few months, they could be left short of players, particularly with the expected loss of Didier Drogba, Michael Essien, John Obi Mikel and Salomon Kalou to the African Nations Cup in January.
Ancelotti is hoping that by the turn of the year he will have both Paulo Ferreira and Joe Cole, currently sidelined with knee injuries, back in action.
"We have very good players and Joe Cole, a very important player for us, will be ready by then," said Ancelotti. "We didn't think we would bring any new players in during January, even before this (ban) happened."