Borussia Dortmund have opened talks with Bayern Munich over the return of Mario Gotze, Bayern chairman Karl-Heinz Rummenigge has confirmed.

"I wouldn't say a deal has been struck, but I can confirm that there have been talks with Borussia Dortmund as well as with his agent," Rummenigge told Sport1 television ahead of Bayern's friendly against Lippstadt on Saturday.

"But it's not complete yet. The clubs must first reach an agreement over a transfer fee."

Gotze moved from Dortmund to Bayern in 2013 after they triggered his €35 million release clause. Dortmund are likely to receive a substantial discount after Gotze failed to establish him with Bayern.