Arsenal midfielder Matteo Guendouzi, who spent last year at Hertha Berlin, has joined Marseille on loan, the French Ligue 1 club announced on Tuesday.
Guendouzi made his Ligue 1 debut for Lorient in 2016 before joining Arsenal two years later.
Guendouzi scored twice in 24 appearances for Bundelsiga side Hertha Berlin last season.
He was called up by France coach Didier Deschamps as cover for Paul Pogba for two Euro 2020 qualifiers but was an unused substitute.
Balerdi, who joined on loan from Borussia Dortmund last summer, has signed a five-year deal.
Marseille had already extended the contract of Spanish centre-back Alvaro Gonzalez and signed young US winger Konrad de la Fuente from Barcelona as well as Brazilian midfielder Gerson from Flamengo.