Zach Hemming's season in Scotland finished on Saturday with his St Mirren side celebrating securing European qualification.
A narrow 3-2 defeat to champions Celtic at the weekend could not take the shine off the campaign's conclusion after a draw with Hearts in midweek - combined with a defeat for Dundee - had already confirmed Saints' spot in next year's Europa Conference League.
It'll be the first time the Paisley club have competed on the continent since 1987.
Hemming, 24, returns to Boro at the end of his loan spell having made at total of 46 appearances for St Mirren, including 15 clean sheets.