While most footballers are busy enjoying their summer holidays, or competing at the World Cup, one dazzling star of the future has been 'signed off sick'.
This is due to his sudden U-turn on his future. After being linked with Arsenal and Liverpool in January, the playmaker dubbed the 'next Ozil' signed a new contract in February, and then declared his intention to quit and play for a Champions League team in May.
With Calhanoglu only signed from the German second division last summer, fans were outraged when reports that he was close to sealing a deal to Bayer Leverkusen followed his statement, he wanted to leave.
The two clubs have been unable to agree a fee, and rather than return to training with Hamburg next month, Calhanoglu has been signed off sick.
He told BILD: "I'm afraid of the fans. It is difficult for me when I see how much anger and hatred is there."
The paper write that it is the internet threats which have got to Calhanoglu, but just seeing what has been written about him, not just to him, has him spooked.
Hamburg chairman Carl Jarchow said: "We will try to ensure that Hakan is quickly ready to play again. We want to help him. We need more information. He is also being investigated by our doctors."
He added: "We do not want to sell Hakan. Eventually, Bayer will accept that."
The youngster is in a problem of his own making, but given Hamburg's flirtation with relegation last season, it's understandable why the Turkish international wants to make a step up.
With 11 goals and five assists, he was a real find of the Bundesliga season. Premier League sides will be interested to learn of the development, having backed off because he appeared close to Leverkusen.
A switch of country may be just what he needs, if Liverpool or Arsenal consider he is worth the trouble, in their own cause to find back-ups for Coutinho and Mesut Ozil.