With Liverpool targeting the Sweden striker, Isak was sent home from Glasgow by manager Eddie Howe on the weekend for Newcastle's friendly defeat to Celtic.
However, Newcastle are insisting Isak is not for sale and he is expected to be on the plane for Asia this week.
"Yes, absolutely. He's part of our squad," Howe said ahead of Sunday's clash with Arsenal in Singapore. "At this moment in time, I expect him to come.
"I'd never give a guarantee about anybody because I've been in football long enough to know I could end up looking silly. But, the desire from everybody to keep him is as strong as it could be. Fingers crossed that will happen for us.
"We love him as a player and a person and want him to stay – and that is right through the club. He's an outstanding talent and a player we cherish. I think for any player speculation's not an easy thing to deal with, and not an easy thing to understand, when you're fielding calls and messages from players and people asking you all sorts.
"The media now is so strong and the media message goes far and wide. I don't think it's easy for any player to be under that scrutiny and that's part – 10 per cent – of the reason why he wasn't here today. I just want him to focus on himself and his training and being ready for next week."