Tottenham and Newcastle have been credited with an interest in the 23-year-old, who signed a five-year deal at Ibrox in July.
"There is nothing anyone can do about speculation," McCoist told the Scottish Sun. "It is always going to happen when a player is doing well.
"But I'd like him to stay here for a long time and win things with Rangers.
"I have no doubt Alan is destined for great things but I believe those great things can be with Rangers."