Isak, who joined Newcastle from Real Sociedad in 2022, has been linked with a move away from the club. However, Howe believes the players will not let this speculation affect their performance.
The 25-year-old Isak has scored 62 goals in 109 appearances for the club, and his absence was felt in Newcastle's 3-2 defeat to Arsenal in Singapore on Sunday.
Howe said the pre-season tour is a time for the team to focus on training and preparation, and not get distracted by external factors.
"The level is so high that even in these games we have to be very well prepared," he said.
Howe praised the players for managing the situation professionally and staying focused on their goals.
Newcastle will face a K-League XI in South Korea on Wednesday, and Howe is confident that his team will be ready for the challenge.