Despite Eddie Howe stating at the weekend that the striker would be part of the first-team group that headed to Asia for a three-match tour, Isak has remained on Tyneside.
Club sources insist the striker’s absence is due to an ongoing thigh problem which needs careful management rather than because of any issues over his future.
It was feared two long-haul flights would be detrimental to Isak’s attempts to recover from his thigh issue in time for the start of the Premier League season.
However, the Swede’s absence from Newcastle’s Asian trip, which will feature matches against Arsenal, Tottenham and a K-League All Stars XI is bound to fuel further speculation over his future.
Liverpool remain keen to sign Isak despite having completed the £79m signing of Hugo Ekitike from Eintracht Frankfurt. The reigning Premier League champions are understood to be prepared to pay around £120m for Isak, who has three years remaining on his current deal at St James’ Park.
It has also been suggested that Isak and his representatives will only enter discussions about a new deal on Tyneside if their demands for around £300,000-a-week are met. That figure would completely shatter Newcastle’s current wage ceiling.
While Isak has not travelled to the Far East, Tino Livramento is part of the travelling party after joining pre-season late following exploits with England at the European Under-21 Championships.
Lewis Hall is also part of the squad, and while the full-back is not expected to be involved in Newcastle’s friendly with Arsenal in Singapore on Sunday, he could feature in next week’s two matches in South Korea.
A Newcastle statement confirming the make-up of the squad that has travelled to Singapore said: “Eddie Howe has an almost fully-fit squad to choose from, however Alexander Isak misses out with a minor thigh injury.
“Lewis Hall is available following an injury lay-off and could feature in South Korea.”