Atsu, 21, signed for Chelsea on a five-year deal from Porto earlier this month before being immediately loaned to Eredivisie club Vitesse Arnhem for the season.
Vitesse have six Chelsea players on loan as part of a partnership between the two clubs, with winger Atsu making the move to gain regular first-team football.
However, it appears that he could have just as easily have ended up in Spain, with Espanyol coach Aguirre having identified him as the perfect replacement for fellow Ghanaian Mubarak Wakaso, who left to join Rubin Kazan.
"First I wanted Christian Atsu (then at Porto), who was the closest thing to Wakaso," Aguirre told Football Espana.
"It went strange, and then Chelsea beat us."
Atsu, who has established himself as a regular for Ghana, made 31 appearances for Porto in all competitions last term, helping them to the Primeira Liga title.
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