Nowitzki wrote a letter that was published as an advertisement in the Sunday edition of The Dallas Morning News.
"From the moment I arrived in Dallas riding on this amazing roller coaster, you lifted me, supported me, pushed me to work harder," Nowitzki wrote.
"So many memories. So many stories. They are not only mine. They are ours.
This is THANK YOU Mavs fans, from the bottom of my heart, for taking in a kid from Wurzburg and making me one of your own.
I will miss playing, but I can't wait to start the next chapter with you.
Forever and grateful, forever yours, and forever a Dallas Maverick."
The words of the letter went over a watermark of Nowitzki's silhouette, a picture of the 2007 NBA MVP shooting one of his famous one-legged fallaway jumpers.
Nowitzki had a stellar NBA career, not only winning a MVP award, but also was a 14-time All-Star and helped Dallas win an NBA title in 2011.
Over his 21 seasons Nowitzki averaged 20.7 points per game with 7.5 rebounds.
His career ends as the NBA's sixth all-time leading scorer.