The 22-year-old centre-back was one of his country's star performers at the World Cup finals just over a year ago, but his representative, Roman Pletz, says he is committed to the cause with Werder.
He told Sky Sports: "At the moment it is not possible for Per to leave.
"He is under contract until 2010 and he is a very important player for Werder Bremen.
"There has been interest in Per since the last World Cup, with English clubs watching him.
"Aston Villa are a big club, but Per is happy at Bremen and he will stay at Bremen this season."