Polish youngster Krystian Bielik has joined Birmingham City on loan from Arsenal for the remainder of the season.
Bielik has made two senior appearances for the Gunners since arriving from Legia Warsaw.
He has all the qualities and ingredients to be a top-level centre-back.
The one thing he is missing is the experience in this position because he came to us as a central midfielder, but I converted him because I felt he can play the type of football we want to play as a centre-back.
Serbian international Branislav Ivanovic has ended his eight-year association with Chelsea by completing a move to Zenit St Petersburg.
Mamadou Sakho has departed Liverpool in order to complete a move to Crystal Palace on loan for the rest of the season.
Southampton have signed striker Manolo Gabbiadini from Napoli in a deal worth a reported £17million.