How tall is Cooper Flagg? Dallas Mavericks' highly discussed height growth speculation finally got a response from trainer
Cooper Flagg can't seem to escape a debate that has nothing to do with basketball. All summer, fans have zeroed in on grainy photos and clips, convinced the Mavericks forward picked up an inch or two before his second season tips off. It got loud enough that his own trainer finally had to say something about it.
Matt MacKenzie has worked with Flagg for years, and when he addressed the rumors this week, he didn't exactly clear things up. What he did offer, though, was a blunt read on how dangerous Flagg's summer work has made him, tape measure or not.
Cooper Flagg's trainer addresses Mavericks star's height growth speculationThe speculation picked up steam over the summer, with plenty of fans convinced that Flagg looked noticeably taller in recent photos and clips. He is officially listed at 6-foot-9, and MacKenzie made clear he has not personally measured his star client to confirm or deny anything. What he could speak to was the work Flagg put in away from the cameras.
Talking to NBA insider Marc Stein, MacKenzie brushed off the height talk and pointed to something he considers far more important heading into the new season.
"I haven't put a measuring tape next to him, so I can't confirm or deny if he's grown in height. All I can say is he's had one hell of an offseason. And no matter if he's 6-9, 6-10 or 6-11, he's going to be a problem," MacKenzie shared in his chat with Marc Stein.
The 6-9 forward was named 2025-26 Rookie of the Year after averaging 21.0 points, 6.7 rebounds, 4.5 assists and 1.2 steals across 70 appearances, numbers that put him in rare company. He became the second rookie since 1973-74 to lead his team in points, rebounds, assists and steals in a single season, joining Michael Jordan on that short list, and he finished as the second-youngest Rookie of the Year winner in league history behind only LeBron James.
Cooper Flagg gets Dirk Nowitzki's guidance ahead of new Mavericks seasonWhile the height chatter played out publicly, Flagg has quietly been getting help from a Mavericks icon behind the scenes. Dirk Nowitzki revealed he stays in touch with Flagg and sends him notes whenever he spots something worth fixing or building on in his game.
Nowitzki, who spent all 21 of his NBA seasons in Dallas and led the franchise to its only championship in 2011, described Flagg as a workaholic who is always hunting for more to add to his game. He said the goal is simply to remind Flagg that he has people in his corner, adding that Flagg is already well ahead of where players his age usually are.
Flagg's second season tips off October 9 with a preseason game against the Houston Rockets in Macao, followed by the regular-season opener in Houston on October 21.
Matt MacKenzie has worked with Flagg for years, and when he addressed the rumors this week, he didn't exactly clear things up. What he did offer, though, was a blunt read on how dangerous Flagg's summer work has made him, tape measure or not.
Cooper Flagg's trainer addresses Mavericks star's height growth speculationThe speculation picked up steam over the summer, with plenty of fans convinced that Flagg looked noticeably taller in recent photos and clips. He is officially listed at 6-foot-9, and MacKenzie made clear he has not personally measured his star client to confirm or deny anything. What he could speak to was the work Flagg put in away from the cameras.
Talking to NBA insider Marc Stein, MacKenzie brushed off the height talk and pointed to something he considers far more important heading into the new season.
"I haven't put a measuring tape next to him, so I can't confirm or deny if he's grown in height. All I can say is he's had one hell of an offseason. And no matter if he's 6-9, 6-10 or 6-11, he's going to be a problem," MacKenzie shared in his chat with Marc Stein.
The 6-9 forward was named 2025-26 Rookie of the Year after averaging 21.0 points, 6.7 rebounds, 4.5 assists and 1.2 steals across 70 appearances, numbers that put him in rare company. He became the second rookie since 1973-74 to lead his team in points, rebounds, assists and steals in a single season, joining Michael Jordan on that short list, and he finished as the second-youngest Rookie of the Year winner in league history behind only LeBron James.
Cooper Flagg gets Dirk Nowitzki's guidance ahead of new Mavericks seasonWhile the height chatter played out publicly, Flagg has quietly been getting help from a Mavericks icon behind the scenes. Dirk Nowitzki revealed he stays in touch with Flagg and sends him notes whenever he spots something worth fixing or building on in his game.
Nowitzki, who spent all 21 of his NBA seasons in Dallas and led the franchise to its only championship in 2011, described Flagg as a workaholic who is always hunting for more to add to his game. He said the goal is simply to remind Flagg that he has people in his corner, adding that Flagg is already well ahead of where players his age usually are.
Flagg's second season tips off October 9 with a preseason game against the Houston Rockets in Macao, followed by the regular-season opener in Houston on October 21.
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