The Wolfsburg player's representative Uwe Kathmann told the Scottish Daily Mail: "Alexander called me on Tuesday and told me that Magath called him in and told him about Celtic's interest.
"He said Celtic wanted him and asked how he might feel about that. Alexander told him he was open to all possibilities but that Scotland would not be his first choice.
"Other big clubs are also interested, but Celtic are playing in the Champions League. The only concern for the player would be the Scottish league.
"We also have other possibilities, but those clubs are still deciding - Celtic are talking to Wolfsburg already."