Dirk Nowitzki made a special gesture Sunday as he thanked Mavericks fans for their support throughout his 21-year NBA career in Dallas. 

On Sunday, Nowitzki took out a full-page ad in the Dallas News. He wrote, in part: "This is not goodbye. 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."

Nowitzki ended months of speculation when he officially announced his retirement April 9 during his final home game against the Suns. He told a packed crowd that they were witnessing his last game at American Airlines Center, but that he hopes to have a role with the Mavericks in the future.

Nowitzki finished his career with a long list of accomplishments as he earned a 2007 MVP award, a 2011 NBA championship and made 14 All-Star appearances. He's also sixth on the NBA's all-time scoring list with 31,560 points.

The full letter can be read below:

Dallas,

Twenty-one seasons.

One team. My home.

No stat, no record, no award in this game means more to me.

We won an NBA Championship together.

From the moment I arrived in Dallas riding on this amazing roller coaster, you lifted me, supported me, pushed me to work harder.

So many memories. So many stories. They are not only mine. They are ours.

This is not goodbye.

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.

-- Dirk Nowitzki