According to British media tbrfootball, Newcastle clubs have different opinions on Isak, and some admit that it is difficult to keep the Swedish striker.
Isaac hopes to leave Newcastle this summer, and Liverpool has made an offer but has been rejected. Sources confirmed to Tbrfootball chief reporter Graeme Bailey that Newcastle president Ruméyan and co-owner Ruben have been involved in negotiations on Isaac's future.
Newcastle senior executives have learned over the past few weeks that Isaac has not only rejected a potential new contract, but also confirmed that he hopes to consider other options. Newcastle has always insisted that Isaac is not a product, but now the problem is open and some inside the club admit that they cannot keep him.
A new contract may turn the situation around, but Isaac's weekly salary is about 300,000 pounds, which is beyond Newcastle's tolerance, and the team's coach Eddie Howe supports the club's position.
Graeme Bailey said: "The next few days will be crucial, and I learned that there are differences within Newcastle about Isaac's future. Although some people think he must stay, others point out that you can't keep a player who doesn't want to stay."
Newcastle is looking for a replacement for Isaac, and they are interested in Sesco, but again, club sources told tbrfootball that they never confirmed that Sesco will replace Isaac directly.
As long as Leipzig's asking price of about 70 million pounds is met, Sesco can transfer this summer, and Newcastle needs to convince the player now. Newcastle's record of signings is £63 million in Isaac, but the initial fee of Sesco £61 million plus additional terms may break the record.