Isak has made his feelings very clear in the past few days as he attempts to force a move away from the club, who he joined three years ago and won the Carabao Cup with last season. The Magpies are at the centre of a bitter transfer saga as the Swedish striker attempt to jump ship to Liverpool which has not worked out so far.
The forward has been the subject of a £110M bid from Liverpool at the beginning of this month which was rejected by Newcastle who are adamant that they need a replacement striker before he leaves. Many pundits have weighed in on the situation, and now Shearer has revealed that he never expected such behaviour from Isak.
"I sat down with him what, five or six months ago, Alex. I didn't see this in him to be honest," he continued.
"I thought he was a manager's dream to be honest, the way he spoke and the way he, sort of, was talking about himself and the club and his life and everything else.
"So obviously something has massively upset him and we don't know that, but those two circumstances, Trent and Alexander Isak, are totally different."
Many have compared the situation to Trent Alexander-Arnold and how he left Liverpool to join Real Madrid but Shearer believes this is nonsense as the right back never refused to play for the club and featured until the very end before his departure.
"Trent was a kid who was brought up Liverpool, he came to the end of his contract. He didn't refuse to play, he didn't refuse to train and then was well within his rights to leave.
"Now, Isak's got three years left on his contract, it doesn't take a genius to work that out does it? Come on."
"I think Liverpool fans' problem is that he (Alexander-Arnold) is a Liverpool lad and they feel like they didn't get a monster transfer fee for him," former England striker Gary Lineker said.
The 25-year-old missed the side’s pre-season training camp and tour of Asia amid growing speculation around his future which is still up in the air and could be for weeks to come.