With a career spanning three decades, Duncan proved incredibly adaptable as the game and his teammates changed around him. Its fair to wonder, however, how he'd fit into todays drastically different NBA.
Offense has exploded league-wide with teams taking as many as 40 3's per game. The 3-point heavy offensive style of today's game contrasts heavily with the post-centric offenses of Duncan's best years, in the late 1990s and early 2000s.
Skilled post players still have room in today's game, of course. That said, they don't necessarily provide the same advantage as they once did.
Two rule changes in the early 2000s helped accelerate the transition away from the post to the perimeter. A 2001 rule change allowed teams to play zone defense, making it easier to double talented post players without leaving another player wide open.
While a 2004 rule on hand-checking allowed perimeter players to move more freely with less grabbing and holding by defenders. As a result, running a post-heavy offense on par with early Duncan-led teams is unlikely to produce a top-five offense now.
How would Tim fare in the modern NBA style?
Instead, Tim would need to expand his range in addition to working on the low block. Duncan was a solid mid-range shooter during his prime, however, being able to knock down threes would determine just how good he'd be now.
Given that bigs of his era (and the era that precedes his) rarely shot threes, Duncan likely never consistently practiced taking them. Despite shooting just 17.9 percent on a limited number of threes, it's possible that he could be an above-average 3-point shooter in 2021.
After all, former Spurs LaMarcus Aldridge and Pau Gasol became good 3-point shooters after years of practice. Were Duncan able to do the same, he'd likely be on par with the best centers in the NBA, including Joel Embiid and Nikola Jokic, as an inside-outside threat.
In his early to mid-20s, Duncan was one of the league's best post players and interior scorers. His rare combination of skill, agility, strength, and length made him a difficult cover for opposing bigs.
Tim would still be a force in the paint against today's big men despite the average big being quicker and more athletic. He'd be able to use his size to gain favorable post-position, his length to shoot over smaller defenders, and up-fakes and step-throughs against more athletic defenders.
In addition to being an inside-out scoring threat, Tim could also be a great offensive hub as a passer. In today's more motion and space-based offenses, he'd be able to find cutters for easy baskets, open shooters, and outlet passes.
Just imagine Duncan throwing a quick outlet pass to the likes of Dejounte Murray or Lonnie Walker, were he playing now.
What About Defense?
Duncan was an all-time great rim protector, blocking more than 3000 shots and altering many more. That said, interior blocking isn't quite as important as it once was. With teams taking so many threes, elite rim protectors can see their defensive value somewhat diminished.
Tim would certainly have to defend further away from the basket now, something that he wasn't asked to do often. Being forced away from the rim would lower his defensive value as well as taking him out of position to grab defensive boards.
Prime Duncan could possibly switch on to some perimeter players and keep them in front of him. Then again, players now are more adept at shooting off the dribble, making that more difficult. It's a tall task for many bigs playing this season, so Duncan might need to drop back when defending the pick and roll.
In doing so, he'd d have a buffer while still being able to contest pull-up jumpers, protect the basket and rebound. It would certainly be interesting to see how a lineup that included Murray, Derrick White, and Duncan would fare on the defense end.
Duncan might not be as dominant playing in 2021 as he was during his two MVP seasons or his legendary 2003 playoff run. That said, were Tim playing in his prime now, it's certainly likely he'd still be one of the league's best players.