Nico Harrison Fires Multiple Staffers After Mavericks’ Disappointing Season

The firings come after the Dallas Mavericks were riddled with injuries during the 2024-25 season.

Dallas Mavericks general manager Nico Harrison walks off the court before the game between the Dallas and the Sacramento Kings. / Jerome Miron-Imagn Images

Dallas Mavericks general manager Nico Harrison is reportedly making more changes to the team's health and performance group, ESPN's Tim MacMahon reported on Wednesday. Per MacMahon, the Mavericks are firing multiple staffers from the group, including athletic performance director Keith Belton and head athletic director Dionne Calhoun.

The Mavericks recently concluded a 2024-25 season that saw Harrison trade franchise superstar Luka Doncic and much of the roster dealing with injuries. Players including Doncic, Anthony Davis, Kyrie Irving, Derek Lively II, and P.J. Washington all missed significant time due to the injury. The depleted Mavericks made the NBA play-in tournament but failed to qualify for the postseason.

Belton, who previously served as the director of football performance at UCLA, was hired last summer. He is now leaving after less than a full calendar year with the team. Belton reportedly had multiple disputes with director of health and performance Johann Bilsborough, who remains a part of the team's staff.

Calhoun was with the Mavericks for 21 seasons and was one of the final staffers from former Mavericks director of health and performance Casey Smith's staff. MacMahon previously reported last month that Harrison felt "threatened" by Smith's impact on the team before firing him in 2023.

Smith was among the staffers Harrison reportedly fired in an effort to help improve Doncic's conditioning and habits off the court. Along with Smith, the Mavericks fired strength coach Jeremy Holsopple and manual therapist Casey Spangler, who Doncic liked working with. Doncic ended up hiring his own training staff, and the Mavericks decided to trade him anyway.

The firings of Belton and Calhoun are just the latest moves of Harrison's that may raise eyebrows surrounding his and the Mavericks' direction moving forward and since trading Doncic.

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