Following a season on loan with Dortmund , Hummels decided to join BVB on a permanent deal in 2009 .
Hummels went on to establish Hummels ' status as one of the world 's top centre - backs .
Following a season on loan with Dortmund , Hummels decided to join BVB on a permanent deal in 2009 and he went on to establish his status as one of the world 's top centre - backs .