The 24-year-old scored 35 goals in all competitions for Dortmund last season as they finished second to Bayern in the Bundesliga, but has made no secret of his desire to join Munich, who also beat Klopp's men in the final of the UEFA Champions League.

A move to the Allianz Arena in this off-season was blocked by the Westfalenstadion outfit, but it appears as though Lewandowski is clear to move to the German treble winners when his contract expires at the end of the 2013-14 campaign.

However, Klopp is hopeful the club and the Pole can maintain a cordial relationship for the new term.

"I think it is a known fact that Robert is going to play for Bayern after the upcoming season," Klopp told Welt am Sonntag.

"Now the only question is how to shape the time until then. 

"That is our concern and it is our commitment to our fans and members to ensure that we will have a more competitive team in the upcoming season. 

"Up to a certain point we were with Robert's desire for change and were ready to talk. But nothing happened so we have to eventually say: '(A sale) now no longer works for us.'"