The Borussia Dortmund forward has a contract with the club until 2017, but is available for €35m next summer.
The German side are keen to keep the 25-year-old, but his representative has refused to rule out a possible switch.
“Marco would make any big European team stronger,” Dirk Hebel told Bild.
“That's why it's completely normal that a number of these major European teams are interested in signing him.
“But his main priority for now is to get back to top fitness and return to the pitch. Everything else is not important at this stage.”
- Sports & Recreation
- Borussia Dortmund
- Dirk Hebel