The Nigeria international left Bolton earlier this week after cancelling his contract by mutual consent.
Shittu found himself out of favour over the last year and did not feature in the first team last season.
A number of clubs are thought to be monitoring Shittu's situation after he impressed during the World Cup with Nigeria.
Celtic are rumoured to be tracking the former Watford man as Neil Lennon considers his defensive options, while clubs in France, Turkey and the Middle East are all believed to interested in the central defender
The 30-year-old feels he had no choice but to quit Bolton as he wants to be playing on a regular basis and he is now considering his options.
"I believe quitting Bolton was the right step to take as I didn't have options to play at Bolton," Shittu told skysports.com. "I wish the club all the best in the future and now I have to find myself a new club.
"I am now reviewing my options and there quite a few interested sides in me from Europe and the Middle East.
"Hopefully I can announce my where my future lies shortly after I return from international duty."