Fortune is available on a free transfer after leaving Bolton last summer.
The 31 year old South African international has struggled with his fitness in the last year after picking up a number of injuries.
"Quinton is definitely looking for a club and there is interest from a few sides," Hayden Evans told Skysports. "Portsmouth have made an enquiry and we are waiting to see what comes of that.
"Ipswich have also shown an interest and there are several others who are keen on Quinton.
"Blackburn are also keeping tabs on Quinton as he impressed there last season and Mark Hughes was lining up an offer for him before he left.
"Quinton is working hard on his fitness and he is an attractive proposition to clubs as he is an experienced and versatile performer."