Munich: Mats Hummels has refused to rule out leaving Borussia Dortmund this summer and says he has "never promised to fulfil his contract".
The defender is the latest BVB player to be linked with a move away from the club following the news Mario Gotze will join Bayern in the summer.
And he admits he remains unsure whether he will see out the duration of his deal, but added that he hopes striker Robert Lewandowski stays at Signal Iduna Park.
"I have never made a promise that I will fulfil my contract in the five-and-a-half years I have been here," he told Bild.
"We know that Robert works in this team - he always scores goals here. I certainly hope that he stays. For me he is the best striker in Europe this year. When you see his development it is phenomenal."
Dortmund set up an all-German Champions League final on Wednesday night after seeing off Real Madrid 4-3 on aggregate, and despite trailing Bayern Munich by 20 points in the Bundesliga, Hummels is confident of springing a surprise at Wembley.
"We have proved our quality. Bayern are incredibly strong after sending Barcelona home at 7-0 and we recognise the achievements of Bayern, but that doesn`t mean they can`t lose a game," he said.
“I don`t know why we would be under pressure, Dortmund fans wouldn`t be surprised if we came second in the Champions League. We are totally looking forward to the game and will stay calm. For Dortmund to play Bayern in the final it is definitely good for Germany.
"The fact that Bayern express themselves with us in mind shows they have noticed us. In all modesty this is probably a result of the reputation we have gained in the last few years.
“We have a lot of quality and a lot of strong players. We are a real community. As a group we have learned from previous seasons."
The two sides face one another in the league on Saturday in what is effectively a dead rubber contest, with Bayern already crowned league champions.