Hamburg secure Ostrzolek signing from Augsburg
The 24-year-old, who made 70 league appearances during his time at the SGL Arena, has agreed a three-year contract with Bundesliga rivals Hamburg.
And Ostrzolek took the chance to explain the reasons for his departure in a statement on Augsburg's official website on Tuesday.
"I had a wonderful time at FCA and I am grateful to the club, the fans and the city," he said. "But I beg you to understand that I want to go to Hamburger SV for a new challenge, because I believe that this is the right move for me.
"I wish FCA all the best and good luck in the future."
Augsburg also announced the arrival of Abdul Rahman Baba on a five-year contract from Greuther Furth - again for an undisclosed fee.
The 20-year-old Ghanaian full-back could well be a ready-made replacement for the outgoing Ostrzolek.