Tim Duncan's reasoning for retiring after 19 seasons is pretty straight forward. Last season became more of a grind and was less fun for the future Hall-of-Famer.

"I started not enjoying myself as much. It wasn't fun as much," Duncan said in an hour-plus interview on the internet radio station Vivid on Wednesday. "When it's not fun anymore, I'm done."

Averaging 8.6 points and 7.3 rebounds in 25.2 minutes a game, Duncan was still productive in his final season. Yet he did suffer a quad injury that kept him out several weeks, so it is quite understandable that after 19 years and at 40 years old, Duncan didn't want to go through the grind of another NBA season.

Duncan has achieved virtually everything throughout his career. He won five championships, two MVP awards and three Finals MVP. He was a 15-time All-Star, selected to the All-NBA Team 15 times (tied for most all-time) and received NBA All-Defensive Team honors 15 times (most all-time).

Yet, even though last season wasn't that enjoyable for him, Duncan is still in awe of all he's accomplished in his career. And as Duncan mentions in a letter to San Antonio on the Spurs website, he wouldn't have become the player he was, if not for the fans:

If I asked to write a script for my career 19 years ago, there is no way I would've been able to dream up this journey

I stand here at the end of this ride and look back in awe of what I've experienced.

The wins and losses will be remembered, but what I'll remember most are the people:

The fans inside the arena and out, the staff and coaches who pushed me and held me together, the teammates (and even opponents) who will be lifelong friends, sharing my ups and downs with family and close friends, and, most importantly, the snapshots of my kids growing up and reveling in watching Dad work.

Thank you to the city of San Antonio for the love and the support over these years. Thank you to the fans all over the world.

A Hall-of-Fame goodbye from a future Hall-of-Famer.