Experienced German international Kevin Grosskreutz has admitted that he could leave Borussia Dortmund this summer.

The 27-year-old's current deal at BVB expires next summer and with no fresh contract on the horizon, the midfielder's future is unclear.

Grosskreutz missed the second half of last season with a series of injuries, but returned to action in Dortmund's pre-season clash against Luzern on Tuesday.

"I am simply overjoyed to be back [playing]," he told reporters. "I have even had doubts whether I would come back at all.

"The next few weeks will now show whether I will continue to play with Borussia Dortmund or not."

Grosskreutz is currently in his second spell with Dortmund.