Bendtner has started only two games for Juve since signing a season's loan deal from Arsenal at the start of the season.
Bendtner's prospects have hardly been boosted by injury, but Arnesen feels the Denmark forward is in over his head at the Italian champions.
“He must take a step down and choose a good club where he can rediscover the joy of playing and playing a lot," said Arnesen.
"“He has said no to me twice because he wanted to play for an even bigger club.
“He must make sure he is always in the best shape and so he should be more humble and think about how he can get the most out of his talent."