That is according to former Germany star Gunter Netzer.
The 24-year-old has been talked up as a Tottenham target, with Mauricio Pochettino keen to make more additions to his squad despite already snapping up Victor Wanyama and Vincent Janssen.
Liverpool were thought to be admirers, however they looked to have pulled out of the race to sign the midfielder.
Although Gotze joined Bayern from rivals Borussia Dortmund for £31million three years ago, Netzer thinks the player looks a shadow of his former self.
"I get the feeling that he is still looking for his former self. He has not developed at all at Bayern. He never really lived up to the expectations at Bayern," Netzer told German paper Sport Bild.
"It depends on his personality whether he should leave Bayern.Â
"It is not an easy step. Should he stay in Germany or move abroad? A move abroad has done a lot of players good, especially those who have a point to prove.
"[Former Bayern coach] Pep Guardiola once said Gotze is the best player he has trained after Lionel Messi, and I can understand that comment. Mario has some incredible skills.
"But they are of no use when you are not showing it on the pitch. He has to prove himself all over again."