Ajax sporting director Marc Overmars fears Marco van Ginkel could stall his career by moving to Chelsea.
The Amsterdam side wanted to sign the 20-year-old Vitesse Arnhem midfielder themselves, but lost out to the Blues.
"Van Ginkel is a great young talent and we would have liked him to come to Ajax," Overmars told BBC Sport.
"Whether it is too early for him to go to Chelsea or not, I don't know. With us, he would have played a lot of games and played in the Champions League."
Van Ginkel was last season voted the best player under the age of 21 in the Netherlands.
He played a key role in helping Vitesse to end the season in fourth, their highest league finish since 1998, and in November won his first Netherlands cap.
Overmars, who won the Champions League with Ajax in 1995 and the Double with Arsenal in 1997-98, has made no secret of his admiration for the player.
But he revealed: "We couldn't have a discussion with the player as Chelsea have a co-operation agreement with Vitesse and were first choice.
"The important thing for the player is that he gets minutes in the first team. Hopefully the deal goes well and he will get into the team."
Tamas Kalas, Patrick van Aanholt and Gael Kakuta were regulars in Vitesse's first team last season after joining on loan from Chelsea.
A Chelsea spokesman told BBC Sport: "We have a good relationship with them [Vitesse], as we do with many other clubs."
Van Ginkel is set to become Jose Mourinho's second signing of the summer, following the arrival of Germany forward Andre Schurrle.