McCoist was told by Rangers director Andrew Dickson of a bid from Bursaspor for Whittaker.
McCoist said: “Yes, I can confirm we had an offer from Bursaspor.
“I took a phone call from Andrew Dickson to tell me about it.
“He didn’t even tell me the figures involved because I told him that I wasn’t interested in selling Steven.
“I have made it clear that Steven is one of the players I see as part of my long-term plans for the club.
“That is why we have opened talks with his representatives to extend his current contract.”