Cooper Flagg to Miss 1st Game of NBA Career, Why is Mavs Star Out vs. Knicks?

Dallas Mavericks star rookie Cooper Flagg reportedly will miss Wednesday's matchup against the New York Knicks due to an illness, per ESPN's Shams Charania.

Mavericks head coach Jason Kidd confirmed the news prior to tip-off.

Flagg has been mostly healthy this season, though he appeared to injure his left shoulder on the opening possession of the Mavs' 101-94 loss to the Oklahoma City Thunder on Oct. 27. The 2025 No. 1 pick played 31 minutes in the game but had his worst performance of his young career, finishing with two points on 1-of-9 shooting and spending most of crunch time watching from the bench.

After the loss, Flagg admitted to being "flat" on the second night of his first NBA back-to-back, and he downplayed the severity of his injury. He turned out to be right, as he didn't miss any time.

Through his first 15 games in the NBA, Flagg has averaged 15.5 points, 6.3 rebounds and 3.1 assists per game. The 18-year-old is still trying to find his footing, but he's shown flashes of immense potential. His best performance of the year so far was his 26-point outing in a loss against the Phoenix Suns on Nov. 10.

The Mavs also lost oft-injured star big man Anthony Davis to a calf injury after five games, and he remains out. And the team is also missing star point guard Kyrie Irving while he continues his recovery from a torn ACL.

With Flagg sidelined, the Mavs have multiple veteran players who will have to make up for his absence. Point guard D'Angelo Russell will likely take over as the primary ball-handler, while wings Max Christie and Naji Marshall all could see increased minutes against the Knicks.