The Swansea City defender, who is known well to Garry Monk and first team coach Dave Adams from their time in South Wales, will spend the season on Teesside as he looks to continue his career development.

Roberts has yet to feature for the Swans, but he made 54 appearances during a season-long loan with Yeovil Town in 2015/16 and made a handful of appearances for Bristol Rovers last season during a six-month spell.

The youthful Roberts follows Jonny Howson, Cyrus Christie, and Martin Braithwaite into the club and he will link up with the squad in Portugal ahead of the final warm-up game in the Algarve, against Chesterfield on Saturday.