Nils Petersen has completed a permanent transfer to Werder Bremen on a four-year contract for an undisclosed fee.
Ozkan Yildirim has signed a new contract to keep him at Werder Bremen until 2016.
Partizan Belgrade have appointed Vladimir Vermezovic as their new head coach following former Chelsea boss Avram Grant's decision to stand down.
The Israeli, who has also had spells at Portsmouth and West Ham, guided Partizan to their fifth consecutive Serbian SuperLiga after taking the reins in January.
Yet despite being at the Partizan Stadium for just five months, the 57-year-old will take charge of his last match this weekend, with Vermezovic his replacement.
Grant refused to speculate on the exact reasons for his departure, telling a news conference: "I would like to keep the details to myself, I planned to stay longer but life is often unpredictable.
"I am sad to be leaving but such is life, we all have to look forward and that means the club, the fans and myself. I opted to activate the clause allowing me to leave before my contract expires."
Vermezovic has a rich history with Partizan, having played for them between 1981 and 1989, while the 48-year-old guided the Black and Whites to the 2005 league title.