Bayern Munich star Philipp Lahm is a £15 million target for Manchester United.

The Sunday Mirror says Sir Alex Ferguson is concerned at his ageing Manchester United defence, with Gary Neville in the twilight of his career and doubts over Rio Ferdinand's long-term future.

Rafael is seen as Neville's successor, but Ferguson sees 25-year-old Lahm as a potential mentor to the young Brazilian.

Lahm is seriously considering his Bayern future after he was fined for publicly questioning Louis van Gaal's role as manager. United are keen to tie up a deal for the German international before his price-tag soars after the World Cup.