Mavericks forward Cooper Flagg, left, and Lakers forward LeBron James watch a free throw during a January game in Dallas. No rookie has averaged more points, rebounds and steals since Glenn Robinson and Grant Hill in the 1994-95 season. AdvertisementDallas Mavericks forward Cooper Flagg watches from the bench as his team competes against Utah on Jan. 15. (LM Otero/Associated Press)“Overall, Flagg’s rookie season has been slightly less than expected,” Hollinger wrote in The Athletic. There’s a reason most rookies don’t play a lot.”MacKenzie said he discusses the grind of the NBA with Flagg often.