Sargent has spent the past two and a half years playing for Werder Bremen in the topflight of German football, having progressed from the club’s reserve side.
De Bruyne’s Chelsea career never took off as he left for Wolfsburg before returning to the Premier League with Manchester City.
Emil Forsberg scored the last-gasp winner in the extra time against Bremen to send RB Leipzig into the German Cup final.
Manchester City playmaker Kevin De Bruyne has signed a two-year extension to his current contract.