[3] Wotherspoon made his NHL debut on December 23, 2022, playing for 14:47 minutes while recording two shots on goal and one hit in the Islanders' 5–1 win against the Florida Panthers.
[4][5] Following six full seasons within the Islanders organization, Wotherspoon left as a free agent to sign a one-year, two-way contract with the Boston Bruins on July 1, 2023.
[6] Although Wotherspoon initially started the 2023–24 season with the Bruins' American Hockey League (AHL) affiliate, the Providence Bruins, injuries to Boston's defense corps caused him to bounce between Providence and Boston for much of the first half of the season.
[7] However, his consistent stability on Boston's blue line earned him a permanent spot on the NHL squad as the team's seventh defenceman,[8] as well as a one-year, $800,000 contract extension on March 8, 2024.
Wotherspoon made his NHL playoff debut in Game 3 of the first round against the Toronto Maple Leafs.