The 23-year-old, who signed a new five-year deal in the summer, is regarded as one of the best central defenders in world football.
"One day I will say that I am keen on a transfer. To play football in a new country would be flattering. I already had offers and one enquiry from these offers was really one of interest for me," he told Bild.
"But I told myself that the time is not right for such a move. There was a reason behind my recent contract extension. When you are a Borussia Dortmund player then you do not move to all clubs.
"In the Bundesliga it would just be about Bayern Munich, but this club has no shortage in my position. In Europe there are just about four to five clubs that would really interest me."