Speaking to talkSPORT Bet, McCoist said: "He [Isak] could play anywhere, at any level. He's probably been the best centre-forward in Europe this year - absolutely terrific.
"Newcastle fans will be building a wall around St James' Park as we speak! I don't think the club would even consider letting him go - unless a ridiculous offer came in. Eddie Howe’s building something there.
"I get that money talks, but selling Isak would send the wrong message. Newcastle are on the verge of a phenomenal season - first domestic trophy in 70 years, possibly a return to the Champions League. That's massive. So while top clubs will come calling, I don't see him going anywhere."