Werder Bremen have officially completed the signing of Sokratis Papastathopoulos, the club announced on their official website.
The Greek international leaves Genoa on a one-year loan with Bremen having the option to purchase the defender outright.
An agreement was long in the making, but financial trouble at the German club stalled negotiations before a deal was finally struck.
"He's a young player and has already gained some experience at Genoa and in the Greek national team," Bremen sporting director Klaus Allofs said.
"When we heard that he was not being used at AC Milan, we immediately expressed interest. With his pace, his strength, and tackling, he will certainly help us."
Papastathopoulos played for Genoa between 2008 and 2010, before being signed by Milan. In a complex deal that involved eight players, Genoa bought back Sokratis in May, only to pass him on to Bremen on Thursday.
"After initial discussions with Klaus Allofs and Thomas Schaaf, it was immediately clear to me that I would accept the offer from Weder. Now I will integrate into the team and help as soon as possible," the 23-year-old said.
Capable of playing both in the centre and on the right of the back four, Papastathopoulos will provide much-needed cover for Bremen's defence. Currently, defenders Naldo, Per Mertesacker, Sebastian Prodl, Sebastian Boenisch, and Mikael Silvestre are sidelined with injuries.