Marc Bola is joining Turkish Super Lig newcomers Samsunspor in a permanent transfer.
The 25-year-old held talks with representatives of Samsunspor at the end of last week and he will join them for an undisclosed fee.
Bola leaves Boro after spending four years with the club.
He made 103 appearances after arriving from Blackpool and he also scored three goals.
The Londoner departs the club after a week that saw six new faces join Michael Carrick's squad at the training camp in Portugal.
Everyone at MFC wishes Marc all the best for the future.