The 21-year-old underlined that the whole team was disappointed with Son not responding to his teammates and that the South Korean international was pressured into making the move by his father.
“I think he is badly advised,” Çalhanoğlu was quoted saying by Goal.
“I have written to him, called him, but he has not answered his phone. I am very sad, the whole team is a bit disappointed.”
“When you’re 23 years old, of course you have respect for your father. But you have to sometimes make your own decisions. We were there for him always – that’s why we are sad. Everyone has tried to reach him.”
Son responded by pointing out Çalhanoğlu having an issue with his move to Tottenham is akin to the pot calling the kettle black.
The South Korean international told Kicker magazine: “People who lives in glasshouses shouldn’t go throwing stones. Everyone should mind his own business and there is certainly enough to take care of.”
Çalhanoğlu joined Bayer on a €15 million move for HSV Hamburg last summer despite his former club wanting him to stay on.
Bayer secured a place in the Champions League group stages yesterday after beating Lazio 3-1 on aggregate. The Turkish international scored the opening goal against the Serie A outfit.
Çalhanoğlu already has two goals to his name this season, the free-kick master scored his 22nd set-piece goal against Hannover 96 last week.
The 21-year-old is expected to start against German reigning champions Bayern Munich next on 29 August in the Bundesliga.