FC Dallas winger Fabian Castillo has completed a loan to Trabzonspor, the Turkish club announced on Thursday.

As first reported by Sports Illustrated and confirmed by an MLS source to ESPN FC, Castillo will play in Turkey at least until the end of 2016 after they clubs agreed a $3 million transfer fee.

FC Dallas also confirmed the deal also has an option for Trabzonspor to sign Castillo on a permanent basis in January for an additional fee, reported by MLSSoccer.com to be between $1-$1.5m.

Castillo visited Turkey last week, but FC Dallas said on Monday that talks had fallen through.

However, Castillo never returned to the United States, and Trabzonspor now says a loan has been signed.

The move will come as a blow to FC Dallas, who currently lead all of MLS with 44 points through 24 games. With the MLS transfer window closing on Wednesday night, the club can not bring in a replacement who is currently under contract with another club.

"We want to thank Fabian for his time with FC Dallas, and his contributions during the last five years," Dallas president Dan Hunt said. "It's been our pleasure to watch Fabian grow from the teenager we all first met in 2011 to the exciting player he is today. We wish him all the best in Turkey."

In six years with the club, Castillo scored 34 goals and 30 assists in 159 regular-season appearances. He had five goals and five assists already this season.

He has earned three international caps with Colombia.

ESPN FC reporter Doug McIntyre contributed to this report.