Doyle is signing a two-year deal with Derby and the Rams hope to obtain international clearance in time for him to be in the squad for today's Championship opener against Leeds United.
The 18-year-old American forward has been training and playing with Derby during pre-season.
He has featured in all of the senior friendlies and scored in the victory over Chesterfield.
Manager Nigel Clough has been impressed with the youngster's performances and the way he has settled in and around the first team.
"Conor is only 18 but when he plays, he doesn't look 18. It is incredible the way he has slotted in," said Clough.
Derby have agreed personal terms with Doyle, who is from Texas and has played youth football in the United States.
He has also been on a scholarship at Creighton University in Nebraska.