The illness issue was revealed by coach Ståle Solbakken. Atiba has been suffering from mononucleosis (AKA "the kissing disease" AKA "Pfeiffer's disease" AKA "glandular fever"). Now I haven't had the thing myself but judging from the list of possible symptoms (fever, Enlarged spleen (!!!), Dizziness or disorientation, Depression etc.) it's just not something that works out with the typical schedule of a professional athlete.
Sources: bold.dk / Hutchinson havde verdens værste sygdom and Wikipedia / mononucleosis.
When I visited a training session last summer Atiba was doing light exercises only due to his illness.
Now he and his agent says he's on his way out of here!
"I don't see myself stay very long. It's a possibility to follow Hangeland because I'd like to play in the Premier League. But Germany, Spain, Italy or France could be fun too."
- Atiba Hutchinson
"A lot of clubs have scouted him and we had interest from England, Germany and France but the price tag has been a problem."
- Andreas Kirsch (Hutch's agent)
(My own not too accurate translations.)
Sources: bold.dk / Atiba Hutchinson klar til større liga, bold.dk / Agent: FCK bremser Hutchinson.