Hato, who is under contract with Ajax, has been linked with a move to Chelsea, although the English club's offer has been rejected.
Additionally, Hato is also reportedly wanted by Arsenal, but Heitinga insists that the defender's absence from the team's friendly match against Celtic was due to fitness reasons rather than any concern about his future.
Heitinga emphasized that Hato is still an Ajax player at present and that his focus is on the players currently under contract with the club.
“I'm not worried about things that are outside of my control,” Heitinga said.
"The most important thing for me is to focus on the players who are part of our team, and to not get distracted by speculation or rumors."