Dallas Mavericks forward Dirk Nowitzki (41) during an NBA basketball game against the New York Knicks Dallas, Texas - 06.03.12 Stock Photo - Alamy

Dallas Mavericks forward Dirk Nowitzki (41) reacts in the second half of an NBA basketball game against the Memphis Grizzlies Thursday, Oct. 26, 2017, in Memphis, Tenn. (AP Photo/Brandon Dill Stock Photo - Alamy

Dallas Mavericks forward Dirk Nowitzki warms up before an NBA basketball game against the Memphis Grizzlies Wednesday, Nov. 22, 2017, in Memphis, Tenn. (AP Photo/Brandon Dill Stock Photo - Alamy

Dallas Mavericks forward Dirk Nowitzki (41) of Germany during the second half of an NBA basketball game against the Los Angeles Clippers in Dallas, Tuesday, Dec. 2, 2008. (AP Photo/Tony Gutierrez Stock

Dallas Mavericks forward Dirk Nowitzki (41) stands on the court during the first half of an NBA basketball game against the Washington Wizards, Wednesday, March 6, 2019, in Washington. (AP Photo/Nick Wass

Dallas Mavericks' Dirk Nowitzki (41), of Germany, attempts a shot over San Antonio Spurs' Antonio McDyess (34) in the second half of an NBA basketball game, Wednesday, April 14, 2010, in Dallas.

Dallas Mavericks forward Dirk Nowitzki (41) in the first half of an NBA basketball game in New Orleans, Wednesday, Nov. 4, 2009. (AP Photo/Bill Haber Stock Photo - Alamy

Dallas Mavericks forward Dirk Nowitzki (41) of Germany attempts to get around the defense of Cleveland Cavaliers forward Ira Newble, left, in the first half of a NBA basketball game in Dallas

Dallas Mavericks' Dirk Nowitzki (41) of Germany drives the ball around San Antonio Spurs' Nick Van Exel in the first half of the NBA Western Conference semifinal basketball game in San Antonio

Dallas Mavericks forward Dirk Nowitzki (41) receives a pass before turning to take a shot in front of New Orleans Pelicans guard Kenrich Williams, rear, in the first half of an NBA

Dallas Mavericks forward Dirk Nowitzki (41) drives to the basket against Utah Jazz forward Mehmet Okur, Saturday, January 28, 2006, at the American Airlines Center in Dallas, Texas. (Photo by Brad Loper/Dallas

Dallas Mavericks forward Dirk Nowitzki (41) in the first half of an NBA basketball game Thursday, March 14, 2019, in Denver. (AP Photo/David Zalubowski Stock Photo - Alamy

Dallas Mavericks forward Dirk Nowitzki (41) dribbles against New York Knicks forward Derrick Williams (23) during

Dallas Mavericks forward Dirk Nowitzki (41) and Denver Nuggets forward Juan Hernangomez (41) in the second

Dallas Mavericks forward Dirk Nowitzki (41) defends the basket from San Antonio Spurs forward Kawhi Leonard (2) during Game 4 of the NBA Western Conference quarterfinals at the American Airlines Center in

Dallas Mavericks forward forward Dirk Nowitzki, left, from Germany, is fouled going to the basket by Portland Trail Blazers forward Juwan Howard during the first half of their NBA basketball game in