Dimitar Berbatov has returned to former club Manchester United.
The Bulgarian, who has been linked with a return to the Premier League, is a free agent after leaving PAOK in the summer.
He has been invited to Carrington to maintain his fitness levels and observe Jose Mourinho's coaching methods.
Berbatov uploaded a picture on Facebook alongside former strike partner Wayne Rooney at United's training ground.
The 35-year-old spent four seasons at Old Trafford, helping the club to two league titles.
He also won the Premier League Golden Boot in the 2010-11 season.
Reports in Bulgaria suggest Berbatov is keen on a return to England, where he also played for Tottenham and Fulham.