Frank Arnesen has raided Chelsea for the second time in three days to sign Jacopo Sala for Hamburg.
Sporting director Arnesen left Chelsea for the German club last month and has followed up the signing of Michael Mancienne by landing Sala.
The 19-year-old attacking midfielder has signed a three-year contract with Hamburg after passing a medical.
The Italy Under 19 international joined the Chelsea Academy from Atalanta when he was 15 and was part of last season's FA Youth Cup-winning side.
"Jacopo is a player with a future," Arsenen told Hamburg's official website.
"He has played for all the Italy youth teams and has excellent technical and physical attributes."
Sala appeared for Chelsea's reserve team last season and is looking for a fresh start having struggled with injuries recently.
"It is a big chance for me to be able to play at Hamburg," he said.
"I would like to continue my development as quickly as possible and to appear for Hamburg in the Bundesliga.
"That would be fantastic, because this big club is something special. Regardless of whether I was in Italy or England - Hamburg are known everywhere."
Arnesen is also hoping to agree a loan deal for Chelsea's 19-year-old Dutch defender Jeffrey Bruma.