Leroy Sane has been warned he 'could end up in the second division' of Turkish football and has been accused of underestimating the game in his new home.
Sane joined Galatasaray from Bayern Munich in the summer for a fee of £12million but the German international has endured a poor start.
Sane did not play at all in the victory over Liverpool in the Champions League and manager Okan Buruk did not even bring him off the bench.
Many believed the 70-cap international would thrive in Turkey and put up big numbers in terms of goals or assists.
But he only has one goal in nine appearances for Galatasaray so far and one of the club's former players Alparslan Erdem, who made 86 total appearances across a number of clubs in the division, has issued a warning to the ex-Man City winger.
He told Bild: 'I think he wasn't fit enough and has to get along first. Gala has now won against Liverpool in the Champions League without Sane. He didn't even play a minute, that's saying something.
Leroy Sane (above) has been warned about underestimating Turkish football
'Galatasaray also had players like Hakim Ziyech, who may not be quite as big a name as Sane, but he wasn't fit enough either.
'He let him play, five, six, seven, eight games and very quickly they let him go. It just didn't work.'
He went on: 'I think Sane underestimated it a bit. He may think that Gala can be done without one hundred percent, but football is not like that.
'No matter where you play, if you're not one hundred percent fit, it happens very quickly and you're suddenly in the second division. He has to be careful.'
But Erdem believes there's one player in the squad to make sure Sane gets it right.
He added: 'I think İlkay Gündoğan will help him a lot because Ilkay is a leader. He'll do it.'
Sane's first major move was from Schalke to Man City for a fee of £54million, which the Premier League side recouped when they sold him to Bayern in 2020.
He scored 61 goals in 220 matches for Bayern, including 13 in 45 matches last season. Bayern had even been keen to extend his deal but he rejected the terms on the table.
The 29-year-old moved on in the summer and despite a number of interested parties, opted to join the Turkish champions.
The former Man City and Bayern Munich star moved to Galatasaray in the summer
Former Tottenham midfielder, Rafael van der Vaart, who is now a TV pundit, gave his verdict on the move when speaking to Dutch outlet RAN.
'I think Sane's development is simply a shame,' he said. 'He threw away his own career.'
Speaking about Sane's exclusion from the national team squad, Julian Nagelsmann had said: 'He has to stand out more. I need a certain quota.'
During his four years in Manchester, Sane scored 39 goals and added 44 assists in 135 games, with the German winning eight trophies, including two Premier League titles.