Sassuolo have completed the signing of Jeremie Boga from Chelsea.
The 21-year-old moves to Serie A after winning two FA Youth Cups as well as UEFA Youth League and Under-21 Premier League titles while at Stamford Bridge, making just one senior appearance for the Blues since joining the academy from Marseille in 2009.
The midfielder impressed during loan spells with Rennes and Granada but his only outing for his parent club came in the shock 3-2 defeat to Burnley on the opening day of the Premier League last season.
He then joined Championship club Birmingham City, scoring twice in 31 appearances in England's second tier.