But the 26-year-old insists that he is happy at Wolfsburg and is not thinking about leaving the club.
The former Bayern Munich midfielder's contract with Wolfsburg is set to expire in the summer of 2018.
"You are happy to know about things like that, still it's an old story," he told Kicker-Sportmagazin. "I am with Wolfsburg and I have a long-term deal at this club."
However, Wolfsburg general manager Klaus Allofs has hinted that the club will consider any bid for the former Hoffenheim player.
"Even at our club, no player is not for sale," he said.
"From my point of view, it's sort of self-evident we would consider any enquiry for one of our players if it is economically reasonable and acceptable in terms of sporting aspects for Wolfsburg."