Luka Doncic reportedly has a rift with a Mavs employee who won millions as a gambler and now acts a shadow GM

• According to The Athletic, former gambler Haralabos Voulgaris has a large influence on the Mavs.
• Voulgaris has reportedly drawn the ire of Luka Doncic, who has snapped at Voulgaris before.
• There is reportedly concern within the Mavs that Doncic could grow tired of the team's front office.
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There is minor tension brewing between Luka Doncic and some in the Dallas Mavericks front office that could have long-term impacts on the team, according to The Athletic's Tim Cato and Sam Amick.

According to Cato and Amick, one of the bigger rifts is between Doncic and gambler-turned-Mavs executive Haralabos Voulgaris.

Voulgaris, whose official title is director of quantitative research and development, rose to fame because of his great success gambling. According to a 2013 ESPN feature on Voulgaris, he made millions gambling on the NBA, developing models that gave him an edge.

In 2009, Voulgaris reportedly consulted for an unnamed NBA franchise. He later became a fixture of the NBA world as a popular user on Twitter and a semi-regular guest on Bill Simmons' podcast.

Voulgaris told ESPN that studying the NBA and its trends led him to believe that he could be more successful at building a team than most GMs.

The Mavs hired him in 2018.

According to The Athletic, Voulgaris' title undersells his role in the franchise. According to the report, Voulgaris has a say in everything from roster decisions to head coach Rick Carlisle's rotations, acting as a sort of shadow GM.

"We had two general managers," a source told The Athletic. Voulgaris's influence reportedly confused other teams about who was making decisions with the Mavs, who have employed Donnie Nelson as GM since 2005.

It's unclear the exact source of Doncic's frustration with Voulgaris, but the two have reportedly had dust-ups.

According to The Athletic, Doncic was annoyed this season when he saw Voulgaris leave a game late in the fourth quarter, as the Mavs attempted to make a comeback (they lost). Doncic reportedly said in the locker room after that he viewed it as Voulgaris quitting on the team.

Doncic also snapped at Voulgaris during a game in February, reportedly saying, "Don't f---ing tell me to calm down," after Voulgaris made a symbolic, downward motion with his hands.

Doncic is eligible for a five-year, $200 million extension this offseason and indicated to reporters that he plans to sign it.

However, according to The Athletic, there is concern that the Mavs' postseason failures (they've been eliminated in the first round of the playoffs in back-to-back years) and dysfunction in the front office could wear on Doncic.

Though Voulgaris' contract with the team reportedly expires this offseason, according to The Athletic, Voulgaris is believed to have a firm supporter in team owner Mark Cuban.

Cuban on Monday tweeted that The Athletic's report was "total bulls---."

-Mark Cuban (@mcuban) June 14, 2021

Doncic is largely on good terms with the Mavs, according to The Athletic, but members of the franchise are concerned that things could trend in the wrong direction without big changes.