Dallas Mavericks officials and staff, both current and former, along with Dirk Nowitzki`s close associates, boarded the team plane to Springfield, Massachusetts in August 2023. The purpose of the trip was to celebrate the induction of the franchise`s most iconic player into the Naismith Memorial Basketball Hall of Fame.
General Manager Nico Harrison was among them. While not particularly close to Nowitzki, their relationship stretched back over two decades to Harrison`s early career at Nike, where he was based in Dallas as an NBA regional representative.
Casey Smith, Dallas`s director of health and performance, also joined the group. Nowitzki frequently credited Smith, who joined Dallas as head athletic trainer in 2004 and advanced to an executive role 15 years later, for extending his career to 21 seasons. Nowitzki deeply trusted Smith, considering him a close friend.
Others present for the Hall of Fame events, which included lavish private parties organized by Nowitzki`s long-time special projects manager Lara Beth Seager, recall nothing unusual during that weekend in Springfield. Harrison and Smith were both accompanied by their wives.
However, subsequent events initiated a series of behind-the-scenes decisions that significantly impacted the Mavericks during a season marked by disappointment, injuries, and underperformance. Interviews with over a dozen team and league insiders reveal that the seeds of the Luka Doncic trade, finalized on Feb. 2, were sown 18 months prior, in the summer before the team reached the NBA Finals. This period marked the beginning of a decline in the franchise`s culture.
Shortly after returning to Dallas from the Hall of Fame event, as the organization was still celebrating Nowitzki`s honor, Harrison requested a meeting with Smith. Smith explained that an in-person meeting was not possible as he was in Ohio with his critically ill mother in her final weeks. They arranged a video conference instead.
During this video call, Smith was informed that his services were no longer required in Dallas, ending his nearly 20-year tenure with the team. Sources familiar with the discussion indicated that the reason for his dismissal was that Smith was deemed “too negative,” interpreted by many as meaning he was not sufficiently compliant.
“He felt completely threatened by him,” a team source told ESPN, suggesting Harrison believed Smith`s influence within the franchise was too strong. “He wanted to assert his authority and ensure no one questioned it.”
This marked the first significant move in Harrison`s overhaul of the team`s health and performance department over the past two offseasons. Smith`s abrupt departure was followed by the firings of athletic performance director Jeremy Holsopple and manual therapist Casey Spangler in June, shortly after Dallas`s NBA Finals appearance.
“Bringing up Casey [Smith] is almost a joke,” Harrison stated during a media availability. “Last year, Casey wasn`t here, and we reached the Finals. No one mentioned Casey then. So, raising his name now doesn`t make sense. He`s been gone for two years. I`m not even going to comment further.”
Sources revealed to ESPN that the strained relationship between Doncic`s representatives – agent Bill Duffy and business manager Seager – and Harrison and his new staff contributed to the decision to trade Doncic to the Los Angeles Lakers for Anthony Davis in February.
Smith, Holsopple, and Spangler were long-serving Mavericks employees who played a crucial role in helping Doncic adapt to American culture after his arrival from Europe as a teenager. They became trusted confidants for the superstar. However, Harrison reportedly viewed them as “enablers” of Doncic, despite their widespread respect within the league. Holsopple was recognized as the NBA`s Strength and Conditioning Coach of the Year in 2021, and Smith`s experience included serving as Team USA`s head athletic trainer during the 2008 and 2012 Olympic gold medal wins.
“We believe the individuals who replaced them are doing an exceptional job,” Harrison commented. “You`re approaching this negatively, but I see it positively. The people we`ve brought in are superior.”
Dysfunction within Harrison`s new hires – director of player health and performance Johann Bilsborough and athletic performance director Keith Belton – has been problematic as the Mavericks faced numerous injuries throughout the season, according to sources. The team has also operated without a full-time manual therapist this season. At one point, the Mavericks struggled to field a team of eight players, falling below a .500 record before finishing 39-43 and securing a play-in tournament spot.
Harrison`s decision to dismiss Smith, and the manner in which it was handled, also alienated Nowitzki from the franchise he dedicated his entire career to. Sources indicated that Nowitzki, who now identifies as a “Mavericks fan,” chose to step back from involvement in basketball operations following Smith`s departure. Nowitzki had previously served as a senior advisor to Mark Cuban, regularly attending practices and offering insights.
ESPN sources also reported that Smith`s exit led to the departure of Mavericks vice president of basketball communications Scott Tomlin, another long-time employee close to Smith, Nowitzki, and Doncic. Tomlin accepted a position as executive director of the DN Companies and The Dirk Nowitzki Foundation.
“My responsibility is to the Dallas Mavericks,” Harrison stated. “It`s about making decisions in the best interest of the Dallas Mavericks, and that`s paramount. Some of these decisions might be unpopular with Dirk and the fans, but my obligation is to the Dallas Mavericks.”
Nowitzki and Tomlin have attended only two NBA games since February: Doncic`s Lakers debut in Los Angeles and his return to Dallas on April 9.
“Over the past year, you could see the team moving in a different direction,” Nowitzki commented in German on his foundation`s podcast. “Now we are seeing the results.”
Dereck Lively II, a young center considered a key player for the future, was listed as questionable on January 20 due to a right ankle sprain, having already missed two games. Under Belton’s supervision, Lively underwent an intense workout before being held out again that night.
The plan was for Lively to play at home against the Minnesota Timberwolves two nights later.
However, Bilsborough expressed concerns, leading to a CT scan for Lively. The scan revealed a stress fracture in his right ankle, sidelining him for over two months.
“Someone should be fired for this,” a team source commented at the time.
Multiple sources indicated this incident was symptomatic of a broader issue.
Harrison, however, portrayed the handling of Lively`s injury as evidence of his medical staff`s “elite” quality. Sources close to Lively expressed satisfaction with Bilsborough`s communication and support during the recovery process.
“It demonstrates the strength of our medical team because he was cleared to play, but our medical team recognized something more based on his symptoms,” Harrison said. “That`s why they conducted further tests and discovered the stress fracture, preventing a potentially serious injury. While you may see it negatively, it`s actually a positive outcome because they identified the issue and prevented him from playing.”
According to over ten team sources, the situation led to a heated argument between Bilsborough and Belton in the practice facility`s trainer`s room and weight room. Harrison did not respond to questions about this or other incidents related to the health and performance group. The Mavericks declined to make Bilsborough or Belton available for comment.
“No punches thrown, but they were going at it,” one source who viewed surveillance footage told ESPN.
“This had been building for a while,” another source added.
The tension had been growing for months. Harrison created an awkward situation by hiring Belton before Bilsborough, even though Bilsborough was to lead the department.
Sources indicated Bilsborough lacked respect for Belton`s expertise.
“He`s just a glorified cheerleader,” a team source said. “But Nico clearly wanted that `cheerleader energy`.”
According to the National Strength Coaches Association, Belton does not possess the required certifications for NBA strength coaches as per the collective bargaining agreement. The CBA mandates that head strength and conditioning coaches have at least three years of certified experience.
An NBA spokesperson acknowledged awareness of Belton’s lack of certifications but stated the league accepted certifications from the College Strength and Conditioning Coaches Association temporarily, expecting Belton to obtain NSCA certifications post-season. Belton`s UCLA bio noted his receipt of the “Stucky Award” for excellence in the practical exam section.
Critics describe Belton as more of a personal trainer than a modern NBA “body engineer”.
“Johann is somewhat restricted in his role,” a source explained. “[Belton] is in a key position training players but doesn`t align with a consistent philosophy or collaborative approach. Furthermore, they have been in conflict from the start, leading to the major confrontation.”
“He has shown Johann no respect all year, offering no collaboration. He’s either standoffish or does reckless things with players just to defy Johann. It`s detrimental, increasing player risk.”
Belton, a former NFL fullback, lacked prior NBA experience. He previously spent four years as UCLA’s director of football performance, among other college roles focused on football.
Bilsborough, an Australian sports scientist with a doctorate, also came from football, having spent five years as the New England Patriots’ performance and rehabilitation director. He also had NBA experience as the Boston Celtics’ sports science director from 2017 to 2020.
A Celtics source described Bilsborough as a highly intelligent academic but not a practical professional, and “divisive when disagreeing.”
Bilsborough and Art Horne, then Celtics head athletic trainer, frequently clashed. Hired in the same offseason as co-heads of Boston`s health and performance, they had no prior relationship.
“It was problematic,” the Celtics source said. “A cold war existed between `Art Horne people` and `Johann people`.”
Communication between factions was infrequent and unproductive, Celtics sources noted. Bilsborough left the Celtics after three seasons, while Horne was promoted to director of organizational growth and team development in 2022.
Bilsborough struggled to connect with Doncic and his personal health team. Harrison had already alienated Doncic by dismissing trusted staff. Bilsborough, replacing the respected Smith, never gained Doncic’s trust or respect, sources said.
Jalen Brunson’s New York Knicks hired Smith as vice president of sports medicine upon his Mavs contract expiry last summer. New York also hired former Mavs athletic trainer Heather Mau. The Knicks` injury rate has significantly decreased, and Smith and Mau oversaw Brunson’s recovery from a severe ankle sprain.
After leaving the Mavs in 2022, Brunson mentioned missing “the Caseys,” Holsopple, and Mau on a podcast. JJ Redick noted his continued group chat with these former Dallas staff members despite his brief Mavs tenure.
“People underestimate their impact,” Brunson said. “They are special, personable, and approachable. It’s more than work; they are genuine people.”
Mavericks sources and player agents are divided on Bilsborough, with some citing his evidence-based approach and competence, while others criticize his lack of player relationships, infrequent team travel early in the season, and overly optimistic injury timelines.
“If you’re not consistently around the team, you shouldn’t be involved in decisions,” a team source stated.
Another source, while praising Bilsborough, added, “Building rapport is definitely a challenge. Casey had that magic touch.”
Harrison defended the Mavericks` health and performance group, citing that most player injuries this season were “unavoidable” contact-related.
However, Mavericks players have re-injured themselves or sustained related injuries soon after returning.
“Contact injuries are one thing, but recovery speed and reinjury likelihood are different,” a team source said. “How quickly and effectively are players returned to play? That’s on the medical and performance staff.”
Another source added, “Dysfunction impacts recovery, compounded by organizational pressure to quickly return players to justify past decisions… The trade itself created organizational dysfunction.”
The most prominent example was Davis’s left adductor strain in his Dallas debut on February 8, returning from an abdominal strain sustained on January 28, just before the trade.
Amidst criticism, Davis was eager to impress Mavericks fans post-trade. He admitted he should have waited longer to return, but the decision was made with his personal medical team and Bilsborough.
“They communicate daily,” Davis said, noting he uses his own weight room staff instead of Belton. “We are all one team.”
Sources suggest this unity doesn’t extend to Bilsborough and Belton’s relationship, whose discord has harmed the team.
“In successful organizations, performance and medical staffs are seamless,” a team source said. “Here, they are separate and opposed. The division’s impact is clear, creating a detrimental environment for players.”
Months before Smith’s exit, Doncic and Seager hired Real Madrid physiotherapist Javier Barrio Calvo and Slovenian national team strength coach Anze Macek to work with Doncic after a quad injury contributed to the Mavericks` draft lottery position in 2023. This followed a trend of NBA stars employing personal health teams in consultation with team staff.
Doncic and Seager envisioned his staff working with Smith, who regularly visited Slovenia and attended Doncic’s national team games. With Smith gone, Holsopple became the Mavericks’ liaison with Doncic’s team.
Doncic’s camp viewed the first season of this arrangement as successful. He led the league in scoring, rebounds, assists, and steals during the postseason and total minutes in the regular season and playoffs.
“You don’t perform like that if you’re unhealthy,” a friend of Doncic’s said, feeling the Mavericks unfairly portrayed the superstar after the trade, ending his Dallas career aspirations.
Despite his performance, Harrison worried Doncic gained weight during the season under heavy workload. Tension grew between the GM and Doncic. Bilsborough inherited a difficult situation and failed to gain Doncic’s trust.
Sources said Cuban, who prioritized Doncic’s happiness since acquiring him in 2018 and had worked with Seager for years prior, offered to mediate. However, Harrison had effectively removed Cuban from basketball operations since Patrick Dumont became governor and resisted any compromise.
Doncic injured his calf in a scrimmage before training camp. Initially thought to be a bruise, an MRI revealed a Grade 1 strain, not disclosed by the Mavericks. Doncic missed preseason and gained weight, frustrating Harrison.
Doncic, using his doctors, was diagnosed with a wrist sprain on November 20. Sources indicated Harrison and the medical staff saw this as a cover for conditioning and weight loss after a slow season start.
On November 29, a closed-circuit feed of Doncic scrimmaging was briefly shown in the media room, showing him taking numerous long jumpers. The channel was quickly changed, and the feed hasn`t reappeared.
Barrio Calvo and Bilsborough communicated but often disagreed. Meetings with Harrison, Bilsborough, Seager, Barrio Calvo, and Duffy were tense and unproductive. Doncic did not work with Belton.
Tension escalated after Doncic’s fourth calf strain in 28 months on Christmas Day. Doncic’s team believed he returned too soon from a heel bruise sustained on December 15. Harrison blamed poor conditioning.
The sides disagreed on Doncic’s return timeline. Bilsborough suggested two to three weeks; Doncic’s team insisted on six. They prevailed, setting a return date for February 8 against Houston.
“That deepened the divide,” a source said.
Doncic avoided weight-bearing for two weeks, using crutches. An MRI four weeks later was positive, but the plan remained unchanged.
Another disagreement arose when Doncic declined Harrison’s request to join a five-game road trip before his return.
Harrison complained Doncic was holding the team “hostage,” sources said.
Doncic’s camp argued that staying at the facility provided better access to workouts and medical equipment. They noted he was doing extensive daily workouts impossible to replicate on the road.
Harrison insisted Doncic needed scrimmages. Doncic’s team offered to have him practice with the G League Texas Legends.
The next communication from Harrison was to announce the finalized trade with the Lakers, negotiated secretly for weeks.
