The simple reason Gregg Popovich loved coaching Spurs legend Tim Duncan

SAN ANTONIO, TX - JUNE 15: Tim Duncan #21 and Head Coach Gregg Popovich of the San Antonio Spurs celebrates after winning the NBA Championship against the Miami Heat during Game Five of the 2014 NBA Finals between the Miami Heat and San Antonio Spurs at AT&T Center on June 15, 2014 in San Antonio, Texas. NOTE TO USER: User expressly acknowledges and agrees that, by downloading and/or using this photograph, user is consenting to the terms and conditions of the Getty Images License Agreement. Mandatory Copyright Notice: Copyright 2014 NBAE (Photo by Andrew D Bernstein/NBAE via Getty Images)

Tim Duncan officially announced his retirement from the NBA on Monday, capping a legendary 19-year career that included five championships, two MVP awards and 15 All-Star appearances.

The Spurs will hold a press conference on Tuesday with coach Gregg Popovich to discuss Duncan's retirement, and fittingly Duncan will not be present.

Popovich, typically a man of few words, will have plenty to say about Duncan on Tuesday, but he's already described in the past how he feels about Duncan.

In an interview with KNBR last year, he explained the simple reason why he loved coaching Duncan so much, which he probably appreciates even more today.

"There are a lot of guys and teams in this league that I couldn't walk in the gym and try to coach them, because I'm going to be too direct, and that's what we believe. If you did poorly, we're going to tell you. If you did well, we're going to tell you. If Timmy isn't rebounding, I'm going to get on him just like the 11th or 12th guy on the team.

"There are a lot of stars out there who can't handle that. They don't want to be criticized at all. But Tim's comfortable enough in his own skin to know that I'm gonna tell him right between the eyes what's going on.

"He also knows that, win or lose, at the end of the day, I'm going to love him, we're going to get a bite to eat, think about our families."