The 23-year-old underwent scans on the injury during the week and revealed on his Twitter page the extent of his lay off.
"For those asking looks like im (sic) going to be out for around 6 weeks... gutted to be injured again but could have been worse," he wrote on his Twitter page tonight.
"Thanks for all of your messages and support, means alot & ill be back on the pitch as soon as i can! thanks again."
The injury is another blow for Karacan, who missed the start of the season with an ankle problem.