'Say it ain't so!': The NBA reacts to Duncan's retirement

Chris Quinn remembers the moment vividly. Quinn was with the San Antonio Spurs, and can still see Tim Duncan sacrificing his body and diving out of bounds in a spectacular effort to keep a ball in play.

It wasn't in a game.

That story was from a practice.

Moments like those that no one saw, moments like the five NBA championships that the world saw and countless other memories from Duncan's 19 seasons with the Spurs were shared by plenty around the game Monday, the reactions coming in swiftly after the 15-time All-Star announced in a simple news release that he is retiring.

''He didn't always wear his emotions on his sleeve like other guys,'' said Quinn, now a Miami Heat assistant. ''So it can get lost how ultra-competitive he is. No matter what we were doing as a team, whether it was a playoff game or a drill in practice, he was trying to win and he was going to do anything in his power to help his team win.''

And Duncan won a lot. Five championships, two MVP awards, three Finals MVP awards and well over 1,000 games in Spurs colors. He's widely considered the best power forward ever, even though the debate will surely still rage as to whether he was a forward or a center (as coach Gregg Popovich insisted he was).

Those are just details now. Power forward, center, agree to disagree.

On Duncan's greatness, there is no debate.

''Say it ain't so!!!'' wrote Dallas' Dirk Nowitzki, who went head-to-head against Duncan a staggering 90 times. ''Greatest power forward ever!''

Added Spurs forward LaMarcus Aldridge, who was with San Antonio for what became Duncan's final season: ''The best PF ever! Thanks for the memories old man. A great player and teammate.''

''Greatest'' was the word that so many of Duncan's playing colleagues in the game used, the list there including the likes of Dwyane Wade, DeMarcus Cousins, Paul Millsap and Austin Rivers.

Even opposing franchises - just about all of them, it seemed - felt it was appropriate to tip their caps. The New Orleans Pelicans called Duncan ''one of the NBA's all-time greats.'' The Miami Heat, the team Duncan faced in his last two NBA Finals trips in 2013 and 2014, called his career ''amazing.'' And the Boston Celtics, knowing that Duncan will one day be honored at the nearby Basketball Hall of Fame, said ''See you in Springfield.''

''Congrats on your incredible career, Tim Duncan,'' the Orlando Magic posted on their Twitter account. ''We thank you for all that you've done for the game.''

The tributes are certain to keep coming. Spurs coach Gregg Popovich is scheduled to talk about Duncan's decision and career on Tuesday in what will likely become an emotional event.

''Probably a top 5 all time player,'' Golden State coach and former Spurs guard Steve Kerr wrote on Twitter, ''and undoubtedly a top 5 all time teammate. Wow, what a career.''

Duncan joins John Stockton and Kobe Bryant as the only players to spend their entire career of 19 years or more with one team. Duncan's longevity was such that when he came into the league Vancouver, Seattle and New Jersey all had teams and Washington's team was called the Bullets. His success was such that the Spurs' celebratory trips to the White House after title years saw them meet with three different U.S. Presidents.

''The ultimate teammate,'' NBA Commissioner Adam Silver said.

In a game where players get as much attention sometimes for style off the court as they do for flash on it, Duncan was different. He mastered the bank shot, one of the many ways he played a simple brand of game exceptionally well. He didn't don super-expensive suits, always preferring the comfort of jeans and casual shirts.

And yet he's still inspiring the generation that follows.

''I wear No. 21 because of him,'' said Philadelphia's Joel Embiid, who was 3 when Duncan made his NBA debut.

On Facebook, longtime NBA forward Etan Thomas shared a story from long ago - it happened somewhere between 2002 and 2005 - about a night that he went up against Duncan and got an education.

Literally, Duncan tried teaching him things. During the game.

''So we're playing the Spurs and I get the ball on the post,'' Thomas wrote . ''I inside pivot and sweep to the middle for my jump hook and he blocks it. So as we are running down the court he says to me `That was a good move but you have to get more into my body so you can either draw the foul or I can't block it.'''

Confused, Thomas wasn't sure if Duncan was being helpful or snarky. A few players later, he tried the move again and made the adjustment that Duncan had recommended.

This time, Duncan couldn't block the shot. Thomas missed anyway, but a lesson was learned.

''He looked at me,'' Thomas wrote, ''and said much better.''