Isak has been the subject of speculation for much of the transfer window, with the forward linked with a move to Premier League champions Liverpool. 

Newcastle has already rejected a reported bid of £110m from Arne Slot's side for the Sweden international, who scored 23 league goals for the Magpies in 2024-2025. 

Isak trained at his former club, Real Sociedad, during Newcastle's tour of Asia and missed the 0-0 draw with Aston Villa on the opening matchday of the Premier League season.

The 25 year-old this week made his first public comment on the saga, suggesting that his relationship could not continue with Newcastle and that promises had been broken. 

Newcastle responded with its own statement on the same day, saying that "no commitment has ever been made" to Isak that he would be allowed to leave this summer. 

Shearer, who scored 177 goals in 348 games for Newcastle, branded the situation an "absolute mess" adding that Isak should sack his agent, Vlado Lemic. 

"If I was him, I'd get his agent in a room and sack him on the spot immediately, because he is meant to be giving him the advice to sign that six-year deal and there's no get out clause," Shearer said.

"I mean, it's ridiculous. And to take anyone's word in football, it's nonsensical to say that someone said, 'Oh, I'll be able to get out at the end of the season.' Really? I mean, come on.

"I've always said there are two sides to every story, but my feelings are exactly the same: he's gone about it in the wrong way.

"I just think even releasing this statement last night has thrown flames onto the fire, which he didn't need to do.

"I get that we needed to hear his side of the story, and we've heard that now, and I'm not saying I don't believe him or I don't believe Newcastle, I'm just saying it's very, very messy for him and for the football club. It doesn't benefit anyone."

Liverpool is expected to return with an improved bid to lure Isak to Merseyside, despite already signing Hugo Ekitike, who was a transfer target of Newcastle this summer. 

Isak has three years remaining on his contract, with Newcastle's statement reaffirming its belief that the player is not for sale unless the Reds meet its £150m evaluation. 

However, with uncertainty surrounding Isak's future, Newcastle has reportedly reopened talks with Brentford for Yoane Wissa. 

It has been reported that Newcastle submitted an improved bid of £35m on Wednesday, including £5m in add-ons, having previously seen their initial £30m rejected.