The Dallas Mavericks have found the problem: their training staff.

After a rocky season in which a swath of injuries wiped out any hope of regrouping following the franchise-changing Luka Dončić trade, the Mavericks are moving on from several senior members of their health and and performance group, per ESPN. It is the third straight offseason in which they have made major changes to the group.

In this case, Mavericks general manager Nico Harrison fired head athletic trainer Dionne Calhoun, who has been with the team for 21 years, and athletic performance director Keith Belton, who was reported last month to be involved in significant infighting over the Mavericks' health decisions.

Viewed from the outside, injuries were a season-killing problem for the Mavericks. Only three players played more than 57 games for the team this season. Kyrie Irving's season ended with an ACL tear. Anthony Davis was immediately sidelined with an adductor strain upon joining the team. P.J. Washington dealt with knee and ankle injuries, Dereck Lively II went down with an ankle fracture and Daniel Gafford missed a large chunk of time with his own knee injury.

This team got so short-handed some began speculating they would have to start forfeiting games due to a lack of healthy players on the roster. 

Somehow, that was only the start of the dysfunction.

In an article published after Dallas' season ending, ESPN reported Harrison's handling of the training staff to be a major fracture point for the team with Dončić and team legend Dirk Nowitzki. Both players were reportedly close with former Mavericks director of health and performance Casey Smith, an award-winning trainer whom Harrison fired in 2023 while tending to his gravely ill mother.

Per ESPN, the reason why was Smith was "too negative." When asked about those claims, Harrison called the Smith situation "kind of a joke" and declined further comment.

Team athletic performance director Jeremy Holsopple and manual therapist Casey Spangler, who were also close with Dončić, were fired last June as well.

Harrison replaced Smith with Belton and director of player health and performance Johann Bilsborough. Belton, a former Chicago Bears fullback, had no NBA experience before joining the Mavericks. He spent the previous four years as the director of football performance at UCLA and technically did not have the certifications required to be an NBA strength coach, though he was approved by the NBA on a temporary basis while seeking those certifications.

On the other side was Bilsborough, an Australian sports scientist with a doctorate who also came to the Mavs from the world of football, in this case five seasons with the New England Patriots. Unlike Belton, he did have NBA experience, working as director of sports science for the Boston Celtics from 2017 to 2020, but reportedly left after clashing with Boston's head athletic trainer at the time.

Those two hires reportedly clashed regularly, with a heated confrontation over the handling of Lively's ankle injury. While rehabbing, Belton reportedly put Lively through an intense workout and believed he could return to action in days. Bilsborough was unsure and sent Lively for a CT scan, which revealed the stress fracture in his ankle. The injury kept Lively sidelined for two-and-a-half months.

There were also reported disagreements with Dončić's camp over injury timelines, as Dončić did not work with Belton at all and believed he sustained a calf strain due to being rushed back from a heel bruise, while Harrison blamed poor conditioning. 

After an MRI on the calf strain, Bilsborough reportedly believed Dončić could return in two or three weeks, while the player's team insisted on needing six weeks. Dončić's trade to the Lakers made it a moot point. Belton is now also gone, while Bilsborough and Harrison remain.

Not everything can be blamed on the training staff, though. Irving's ACL tear was described as a freak accident, but also came while the 33-year-old guard was shouldering the NBA's biggest minutes workload in the wake of the Dončić trade.

You can take that one up with Harrison.