Hleb, who failed to impress in his first season at the Nou Camp before being loaned out last summer, told Bild: "I'm going back to FC Barcelona, where I have a two year contract.
"I want to go there and make the breakthrough. I want to prove to myself and everyone else that I can play at the highest level."
As for his relationship with Gross, Hleb said: "From day one he has criticised me. If I'm dribbling, he has criticised me. If I have not played the ball right back, he has criticised me. I have the feeling that everything I do is wrong."