Chelsea football chief Michael Emenalo was in the stands on Sunday for Vitesse Arnhem's 0-0 draw with FC Twente.
Emenalo was making a check on Chelsea's on-loan players, including Patrick van Aanholt and Tomas Kalas.
However, it's understood he was also running the rule over Vitesse striker Wilfied Bony, who is under consideration at Chelsea for a January move.
Kalas has already urged Chelsea chiefs to sign Bony in the past week.