Former Bayern Munich star Michael Ballack does not believe Bayer Leverkusen youngster Kai Havertz should move to the club.
Havertz is being linked with a move in the summer transfer window, after interest from several top clubs.
He is wanted around Europe, with Liverpool, Chelsea and Manchester United all linked, as well as Bayern.
But Ballack does not believe the winger is ready.
"At Bayern you need other characteristics to assert yourself. Just being good is not enough there," Ballack told Sport1.
"[Havertz needs] time and the robustness to be mentally prepared for Bayern.
"He is still in the development phase and still has mistakes in his game."