Date published: Friday 11th October 2019 1:49
The 19-year-old joined Chelsea from Ajax in 2016, but completed a loan switch back to the Dutch giants who also have an option to buy the defender.
However, Castillo has revealed that he nearly joined Serie A champions Juventus before the deal fell through.
Castillo penned a new Chelsea deal – for whom he is yet to make a senior appearance – before completing the loan move to Ajax.
He told Dutch magazine Voetbal International: “Things happened so I finally chose Chelsea.
“Chelsea is a big club, so I am happy with my choice anyway. That I could be loaned out to Ajax, that is absolutely beautiful.
“I was actually supposed to go to Juventus. That was the number one. For some reason, that was cancelled. Now it is up to me to continue.”
Castillo admits he is hoping to make a positive impression back at Ajax and convince the Dutch giants to then activate the purchase option to keep him permanently.
“Ajax loaned me with an option to buy. If I do well this season I hope that I will be bought and that I will get more minutes in the Eredivisie.”
The defender is currently featuring for Ajax’s second string, Jong Ajax, who play their football in the Dutch second tier, and will look to work his way into contention for the senior squad.
Castillo has not made a single senior appearance for Chelsea.