Dietmar Hamann says Pep Guardiola is leaving the best league in the world by walking away from the Bundesliga and may find the experience of English football underwhelming.
Guardiola will depart Bayern Munich at the end of the season to take the helm at Manchester City, replacing Manuel Pellegrini for the 2016-17 campaign.
After announcing his decision to not to sign a new Bayern deal, the former Spain international confirmed his intention to test himself in England, often hailed as one of the most passionate football environments in the world.
But former Liverpool, Bolton Wanderers and City player Hamann has warned the highly rated tactician to prepare for a rude awakening in the Premier League.
"After his time in Barcelona and Munich he will be surprised," Hamann wrote in Kicker.
"When he experiences the atmosphere in an English stadium he might think he was in Unterhaching," he added, referring to the Bavarian minnows playing in one of Germany's regional competitions.
"The Premier League is not the best league in Europe - the Bundesliga with its attacking, skilful style has the most attractive product."
Hamann also offered a grim warning about the state of the next domestic competition Guardiola will attempt to conquer, claiming the seemingly rude financial health of the Premier League is in fact a "huge bubble" which has not resulted in international success for English clubs or the national team.
"The Premier League is heading straight into a crisis," he said.
"The inflationary rise of TV money to two, three billion Euros does not improve the level at all ... if every player who is able to walk straight earns three million per year, that is dangerous for the English clubs.
"The English [have shown] during the last five years that money is no guarantee for success."