Boro have agreed that Andrew Davies can go to Southampton on a three month loan and the club are willing for this to become a permanent move in January.
Davies wants to leave due to his lack of starting opportunities at the Riverside.
The 22-year-old defender has made 49 starts for Boro since his debut nearly five years ago. He has also played for QPR and Derby on loan in the past, making 32 starts, 23 of them for Derby.