Former Newcastle midfielder Kevin Nolan has voiced his concern at the ongoing speculation surrounding Alexander Isak’s future.The Swede has attracted interest from Premier League champions Liverpool this summer while also being linked with a money-spinning move to Saudi Arabia.Alexander Isak’s future is no clearer after images surfaced of him training alone on TuesdayGettyIsak was left out of Newcastle’s pre-season clash at Celtic on Saturday with boss Eddie Howe admitting he wanted to remove him from ‘scrutiny’ over speculation he may leave the club.Howe later revealed that Isak would be part of his side’s tour of Asia which kicks off this week ahead of a clash with Arsenal in Singapore on Sunday.However, images have since surfaced of the striker appearing to train alone on Tuesday.The pictures were made public on the same day talkSPORT reported that Isak had hit Newcastle with a blockbuster wage demand of £300,000 a week.And now speculation is gathering pace over whether Newcastle have chosen to banish the 25-year-old to individual training until his future is sorted out.Nolan, who spent two years on Tyneside, believes that a manager has to make tough decisions for the betterment of his squad.“I think if a player came in with that attitude you’ve got to make a decision for the rest of the squad,” the Northampton Town boss told talkSPORT. “That may have happened if he’s training on his own.“You never know these days, he could have a family issue or it could be for personal reasons so they’ve given him a little bit of time for him to be off for three or four days then come back and reintegrate him into the squad.“That’s what goes on a lot these days.”Isak has netted a respectable 62 goals in 109 games for the Magpies since joining the club from Real Sociedad in 2022.View Tweet: https://t.co/RCTSA4hcwAIsak netted 26 goals last season as Newcastle ended their 70-year wait for a trophyGettyKevin Nolan says an Isak departure would serve as a huge blow for the MagpiestalkSPORTHis 26 goals across all competitions last season garnered the attention of Liverpool who were ready to splash a whopping £125million to secure his services.While the Magpies are keen to retain the services of their star man, Isak’s £300,000 wage demands leave them in a position where they will need to break their wage structure to keep hold of the striker.“I think if you’ve got the majority of Newcastle fans on I think they’d be saying ‘yeah, we want to keep him, pay him the money. We’ve got the owners now and the backers,’” Nolan added.“Are you going to find another Isak? They’re talking about [Yoane] Wissa but I’m not too sure he gets the goals and becomes the No. 9 because it’s different.“No disrespect to Brentford but it’s different playing at Newcastle. Being the No.9 at Newcastle compared to Brentford, there’s an expectation there.“You’re not just going in to take the historic No.9 shirt, you’re also replacing Isak. It will help him if he’s alongside Isak.The Magpies are readying a bid of around £30m for Yoane Wissagetty“If they lose Isak, I think it’s a major blow to Newcastle and where they are trying to go.”Who else have Newcastle signed?Newcastle have secured the signing of Anthony Elanga so far this summer in a £55m deal as Howe looks to strengthen his squad ahead of a busy campaign of domestic and European football.The Magpies held an interest in Bryan Mbeumo before his switch to Manchester United before seeing a bid for Eintracht Frankfurt’s Hugo Ekitike rebuffed.Nolan believes that Newcastle may need to aim higher on player valuations in order to land future targets.“When clubs know you’ve got money to spend, they want to take a bit more off you,” he said.“I think you have a valuation in your head as a club and I think sometimes they haven’t been able to go to the [selling club’s] valuation of a player.“It’s going to be interesting for the next four or five weeks to see where Newcastle and Eddie go because they need reinforcements because they’re going into the Champions League and have the Premier League to deal with.“They’ve got to be competitive in both. They’ve got to be in the top four at the end of the season and have a really good go at the Champions League.”