In-form Bayern striker Lewandowski must make groin op decision

The 31-year-old Lewandowski is in the form of his career having scored a phenomenal 20 goals in 16 matches this season, including 14 in the first 10 league matches, a new Bundesliga record.

He is currently on course to break Gerd Mueller's incredible record of 40 goals in a Bundesliga season and will play in Wednesday's Champions League match at home to Olympiakos, as well as Saturday's league match against his former club Dortmund.

However, the Poland hot-shot must decide when to undergo surgery.

"We were surprised to read about this in the press," admitted Flick in his first press conference since replacing Niko Kovac, who was sacked as Bayern's head coach on Sunday.

"He (Lewandowski) has problems, but no pain and it's clear that something has to be done. He will think about when he wants to have it. It would not be good to interrupt the run he is having but it will be his decision and we have to respect that."

Lewandowski is the highest scoring foreigner in Bundesliga history with 216 goals in 300 matches, for Bayern and Dortmund.

The Poland captain has also scored 60 goals for his country in 110 internationals.

According to reports, one option would be for Lewandowski to have the surgery during the international break, which starts next week, with Poland having already qualified for the Euro 2020 finals.

Poland play Israel away in a qualifier on November 16, then face Slovenia in Warsaw three days later.