Per league and club policy, terms of the deal were not disclosed.
Yartey, 25, has made 27 league appearances for Swiss first division club FC Sion since joining them on loan from French Ligue 1 club FC Sochaux-Montbéliard at the start of the 2013-14 season. Prior to his move to Sion, Yartey made 15 appearances in one season with Sochaux’s first team.
Yartey spent 2009-2012 under contract with Portuguese giants Benfica. He started 31 games while on loan at Swiss Super League side Servette FC in 2011-12, scoring eight goals for the club. He also had loan stints with Portuguese clubs Beira-Mar (2009-10; 2010-11) and Fátima (2010).
A former Ghanaian youth international who scored once in their fourth-place finish at the 2007 FIFA U-17 World Cup, Yartey was called up to the Black Stars’ senior side for two 2014 World Cup qualifiers in 2012 but did not appear in either match