[1] Ostapchuk was signed by the Senators to a three-year entry-level contract on September 29, 2021.

[2] He was assigned to Ottawa's American Hockey League (AHL) affiliate, the Belleville Senators to begin the 2023–24 season.

[3] On March 12, 2024, Ostapchuk was called up to Ottawa after an injury to Rourke Chartier and he made his NHL debut later that day against the Pittsburgh Penguins.

[5] He was recalled in October and made his NHL season debut on October 29,[6] and recorded his first NHL point assisting on Noah Gregor's goal in an 8–1 win over the St. Louis Blues.

[10] This Canadian biographical article relating to ice hockey is a stub.