"I will once again become Dortmund's number one striker," he said in an interview with German daily Bild.

Frei has been used mainly as a substitute since recovering from a serious knee injury he sustained while playing for Switzerland at EURO 2008.

Egyptian forward Mohamed Zidan and Paraguayan Nelson Valdez have been Jurgen Klopp's preferred partnership upfront this season.

However, Frei is not ready to throw in the towel and is not looking to leave Dortmund.

"I would have to be stupid to want to leave at the first sign of any difficulties. My relationship with these unbelievable fans is unique," he added.