Gotze joined the current Bundesliga champions from rivals Borussia Dortmund in 2013, but has yet to live up to expectations at the Bavarians and is touted fora move away from the Allianz Arena.
Netzer has also not been impressed with Germany's 2014 FIFA World Cup hero and stresses it is time for Gotze to prove himself.
"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 Sport Bild.
"It depends on his personality whether he should leave Bayern. 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."
Gotze has been linked with a possible return to Dortmund, while Liverpool and Juventus are also reportedly interested in his services.