Germany and Bundesliga legend Rudi Voller believes Robert Lewandowski remaining at Bayern Munich could cause problems if the higher powers continue to refuse to sell him.

The Poland striker has expressed his wish to leave the club after eight remarkable seasons where he has won the league title in every campaign.

Barcelona wants to sign the 33-year-old despite their money worries and Bayern appears to have found a part replacement for Lewandowski, with media reports saying Liverpool's Sadio Mane is set to undergo a medical on Tuesday.

There is still a chance that Lewandowski stays in Munich with one year left on his contract and former Germany coach Voller, who has just retired as Bayer Leverkusen's managing director, is watching the situation closely.

"If Lewandowski stays, then he must give a clear commitment, then the one year is still possible, otherwise it will be difficult," Voller told Bild TV on Sunday.

Buying Senegal's Mane is a "top transfer" as his "career has so far been outstanding" according to Voller, who added: "They have done very well and perhaps it is in case Lewandowski leaves. Bayern have a top team even without him and can win the Champions League."

But former Liverpool forward Dean Saunders is perplexed by the 30-year-old Mane's impending move to Bayern, believing the Bundesliga will be too easy for him compared with the Premier League.

"Nothing against the club, it’s a great club, but the league is nowhere near a challenge for Mané," he told Talksport.

"He will get in his armchair, light a cigar up, he’ll play for Bayern in third gear and he’ll coast for two years and ruin the best two years of his life as a footballer."