Baba Rahman has completed a season-long loan move from Chelsea to Schalke.
The Ghana international left-back, 22, has returned to Germany after failing to impress following his move to Stamford Bridge from Augsburg a year ago.
He made 15 Premier League appearances for the Blues last season, four of them as a substitute.
His performances for Augsburg during the previous season attracted interest from a number of European clubs.
He has been reunited with his former Augsburg boss Markus Weinzierl, who took charge at Schalke this summer