Tiemoue Bakayoko moved to AC Milan on a one-year loan deal on Tuesday after just a season at Chelsea.
Milan announced the move in a statement on their official website and also confirmed there is an option in the deal for them to eventually sign the midfielder permanently.
Bakayoko will be unveiled as a Milan player on Friday.
Competition for places in the Chelsea midfield is fierce following the summer additions of Jorginho and Mateo Kovacic.
N'Golo Kante is a guaranteed starter when fit, and new Blues manager Maurizio Sarri started January signing Ross Barkley alongside the Frenchman and Jorginho as Chelsea beat Huddersfield Town 3-0 on Saturday.