Ravel Morrison has returned to parent club West Ham from Cardiff City on compassionate leave.
Brighton boss Sami Hyypia is weighing up a move for former France captain Alou Diarra.
Hummels has long been linked with Spanish giants Real Madrid and Barcelona, but the 25-year-old is happy at the Signal-Iduna-Park.
The former Bayern Munich stopper admits that he is not driven by winning lots of trophies.
"I do not necessarily need to play for the best team in the world to remain in a situation to have a certain chance to grab trophies. That's a fact," he told Die Welt.
"I am a player of Borussia Dortmund and, so to say, I would prefer one UEFA Champions League title with Borussia Dortmund over six with an other club."