Chelsea duo Mason Mount and Fikayo Tomori will be forced to watch from the sidelines when Derby face the Blues in the League Cup.
The London Evening Standard reports that Chelsea will not allow the two players to feature against their parent club later this month.
Derby boss and former Chelsea player Frank Lampard has previously admitted that he would be discussing the idea with his former side, but the Blues are now unlikely to agree to the deal.
League Cup rules state that players are free to face their parent club, providing the team in question gives them the go-ahead to do so.
However, throughout all of their loan deals, Chelsea are keen to avoid coming up against their own players and add in such a clause to any deal.
Both Mount and Tomori have been key for Derby this season and were influential during their victory against Manchester United in the previous round.
