Backpicks GOAT: #7 Tim Duncan

Key Stats and Trends

  • Elite defensive metrics and a key to the best defensive dynasty since the ’60s
  • Strong isolation scoring and good creation helped him carry weaker offenses
  • Mediocre passing and outside shooting limited offensive scalability

Scouting Report

For a decade, Tim Duncan’s game was so similar that his different seasons were only distinguishable by hair style. He was quicker in his early years, allowing Gregg Popovich to deploy him as a small forward during his rookie season on a triple-tower frontline with David Robinson and Will Purdue; Duncan even guarded point guards at times!1 He was mobile enough to contain guards on switches, then recover and protect the rim:

That play highlights his tendency to block shots at their point of release instead of in the air, near their apex. From a psychological perspective, this habit might have cost him a Defensive Player of the Year award to sexier, aerial shot blockers.2 Duncan was still agile enough to tally the occasional Sportscenter block; in the next clip, he tracks the ball before using his length to erase a layup:

Duncan called on his deceptive reach to constantly interfere with shots in the paint. In the first clip below, notice how he’s positioned perfectly, allowing him to impact the attempt with a quick reaction:

Although his reactions weren’t always this quick, when he was locked in on the ball and ready to pounce, he provided elite rotations in his prime. In the next clip, he loiters near the 3-point line to safeguard on Dirk Nowitzki’s trail, then recovers to help at the rim:

I tracked about 800 Duncan possessions from 1998-2008, specifically looking at these rotations, and his tendencies were steady throughout his career. He rotated “well” on 4 plays per 100 and provided an “elite” rotation play, like the previous one, about once a game. For perspective, this was two-and-a-half times the rate of Shaq’s quality rotations but 20 percent below David Robinson’s frequency during their primes.

Naturally, he was a low-error defender, with most of his breakdowns coming when he switched onto quick offensive wings. In sampling him for this series, Duncan was in the top quartile of defensive error rates, and in my 2010-11 tracking he was in the 91st percentile.3 He could hold his own against many perimeter players, fluidly switching and then recovering:

Sometimes, he was reluctant to stray too far from the hoop and would often sag back in pick-and-roll coverage, conceding space on outside shots. His on-ball defense was quite good against other big men, as he used his length and lower body strength to hold position and disrupt shots, even against the strongest of giants:

Most wings were reluctant to challenge him in the lane, and his wingspan allowed him to blanket the paint. His only notable defensive weakness was a lack of top-end quickness that prevented him from making certain five-star saves:4

As he aged, more of his rotations were a half-step slow, although he was still better positioned than most. He was also a phenomenal defensive rebounder, posting 11 relative rebounding seasons above the 94th percentile historically (+12 percent or better), peaking in the 99th percentile.

On offense, Duncan was no slouch either. His patented move was, of course, the face-up banker:

But he didn’t call on that as much as advertised. Instead, he owned a full arsenal of post moves from day one, including hooks, fades, and drives:

In those clips, notice how powerful he is, rooting down into the floor and holding positions near the basket or dislodging defenders on his penetration. This wasn’t Shaq or Wilt strength, but at 250 pounds, his sturdy base moved opponents and claimed valuable interior real estate. He had some agility too, and his spin move was one of his most effective attacks:

At times, he pounded the ball too much, symptomatic of the isolation malady of the late ’90s. This slowed down the offense and ate enough clock that, sometimes, no other options were available:

He was also a fantastic offensive rebounder, using his size to carve out space near the rim, then his length to snatch the board:

Among top-1,000 scorers, Duncan’s offensive rebounding rates were above the 86th percentile in every one of his first 13 seasons, peaking in the 93rd percentile. During his prime, he turned this into offense, tapping in his own misses as part of his attack:5

Duncan wasn’t a great outside shooter, as shot-chart data for his career pegs him at around 40 percent from the midrange and 39 percent on long 2-pointers, limiting his value as a pick-and-pop player or finisher. He was never a great passer either, although he improved as his career unfolded. He could hit a basic, first-level cutter, and developed an ability to find skip passes when doubled:

However, he lacked vision to make elite passes, sometimes struggling with double-teams, failing to read the defense correctly:

He was even blind to easy passes early in his career, and although he improved his reads, the poor vision remained nearly a decade later:

In my sampling, prime Duncan made “good” passes on under 2 plays per 100 possessions, slightly more often than he threw “problematic” ones such as those shown above. His creation rates were solid and undersold by the classic Box Creation estimate, more accurately captured using the non-3 version of the metric. In tracking, he peaked around 7 shots created per 100 during his peak years, and was closer to 4 or 5 in the surrounding seasons.

Duncan’s quickness started to fade in 2005 and he battled nagging injuries during that stretch of his career. As he aged, his defense slowed slightly — he couldn’t stay with wings as well, he couldn’t cover quite as much court, and he couldn’t react around the goal quite as quickly. Still, Old Man Riverwalk was so positionally sound and lanky that he remained an impact defender through his final seasons:

He wasn’t quite the same offensive weapon by 2009, still chock-full of post moves, just at slower speeds. He improved as an extra-passer in his final act, serving as valuable connective tissue in the Spurs hot-potato offense. By 2011, his isolation shifted into full old-man mode, relying on guile to provide post scoring in bursts. He slimmed down and was able to play effectively in limited minutes until 2015, his 18th season.

Impact Evaluation

Duncan’s polished game made an immediate impact in San Antonio. His team defensive metrics were historically good, as were his individual plus-minus metrics. When asked to carry the load, his postseason scoring was excellent, but San Antonio’s offenses really took off when Duncan’s role diminished, a testament to the unparalleled coaching of Gregg Popovich.

Duncan joined San Antonio in 1998 in one of the great turnarounds in NBA history. With David Robinson returning from injury, the Spurs added 11.3 efficiency points to their relative defensive rating (rDRtg), by far the biggest single-season improvement ever.6 Per the scouting report, Duncan was an immediate impact defender, and despite logging time at small forward, he still posted a block rate in the 84th percentile as a rookie.

Teams struggled at the rim against the Spurs with Robinson on the court, but according to rim protection metrics, they were even worse with Duncan in the game. Opposing field goal percentage is a noisy stat, but it supports Duncan’s dominion over the lane that we saw in the scouting report:7

Duncan’s arrival spawned the most dominant defensive dynasty of the 3-point era. While credit must be given to Popovich and studs like Robinson and Bruce Bowen — two of the best defenders ever at their positions — Duncan was an impressive centerpiece on San Antonio’s backline for more than a decade. The ’98-02 Spurs authored the second-best five-year defensive stretch of the 3-point era, with an rDRtg 5.6 points ahead of the league, slightly behind the ’90s Knicks’ mark of -6.1. (The lower the rDRtg, the better.)

When Robinson retired after the 2003 season, the Spurs paired Rasho Nesterovic alongside Duncan in the middle and improved by 4.9 points on defense, finishing with the best rDRtg in the 3-point era (-8.8) in 2004. This kicked off a new, five-year run that bested their ’98-02 mark, in which San Antonio’s average relative defense was an incredible -7, making Duncan a linchpin on the best regular season and postseason five-year periods of the modern era:8

In 2004, the rules (and officiating) rewarded physical defensive styles like Bowen’s and Duncan’s, and Popovich was a master of exploiting the rulebook, bringing in Robert Horry and upping Ginobili’s minutes — both savvy plus-defenders. (Horry was known for clutch shots, but he was an excellent team defender and strong passer during his prime.) The Spurs posted an impressive -6.3 rDRtg in 13 games without Duncan that year, so the defense was elite without him, but he also made a sizable impact.9

Since he played his entire career in the play-by-play era, we can corroborate Duncan’s defensive impact with plus-minus data. He holds three of the top-50 defensive adjusted plus-minus (DRAPM) seasons ever recorded, and his scaled four-year peak ranks second, behind only Kevin Garnett. If we weight values by minutes per game — accounting for years in which his per possession impact was lower but his overall game impact was higher — Duncan’s four-year peak ranks second to only Dikembe Mutombo. Here’s how Duncan’s minute-weighted defensive APM compares to Garnett’s throughout their careers (individual seasons and their all-time rank are included in the background):

Duncan’s drop-off on the back nine of his career coincided with his gradual loss of movement that is noticeable on film. Still, his ability to maintain defensive prowess for nearly two decades is astounding. Excluding their injury-plagued 1997 season, the Spurs have posted an above-average defensive rating in 27 of the last 28 years (!) and in 22 of those seasons they were at least 3 points better than league average. With Duncan, their only seasons worse than -3 came in 2011 and 2012, before a slimmer Timmy bounced back with new defensive talent like Kawhi Leonard.

Offensively, Duncan’s assemblage of scoring moves and moderate creation moved the needle as well. While he never crafted a huge scoring season — his career-best rate of 25.1 points per 75 ranks 280th all-time —  Duncan’s post game was the centerpiece of the Spurs offense during his peak years, and the team finished with an above-average attack in each season from 1999-2003. However, they never created too much separation with this approach, topping the +1.5 rORtg mark only twice (when healthy) in Duncan’s first seven seasons. Those early teams were constructed for defense while Duncan kept the offense afloat.

Timmy became the offensive focal point in 1999, leading them in load as Robinson dialed back his attack. The Spurs offensive rating improved from slightly below-average to slightly above-average en route to a 61-win pace (7.1 SRS) and a title. Those teams lacked a perimeter creator, so they played an inside-out game, with 3-and-D wings like Jaren Jackson and Mario Elie flanking Duncan. Then in 2001, they leased Derek Anderson for a year, who was a perimeter threat that served as a low-grade second option. The team shot a fiery 40.7 percent from downtown and produced what was easily the best offense of Duncan’s prime (+3.6 rORtg).10

Like a handful of other greats in this series, Duncan’s arsenal was resilient against stingier playoff defenses. In the single postseason he missed (in 2000), the Spurs rORtg was -8.1 for four dreadful games, the only year of his prime that his team’s playoff efficiency fell below average. Below, I’ve compared him to the other great modern bigs in the Big 3 box categories during their three-year peaks, first in the regular season, then in the playoffs. While his regular season scoring efficiency never stood out, he maintained it in the postseason when most trailed off:

At his apex (’02-04), he actually upped his efficiency and creation in 44 playoff games. That’s not a cherry-picked sample, either — any three-year playoff stretch until 2006 would look similar. Duncan’s often lauded for his ’03 season, but his 2002 season may have been more impressive. The Spurs posted a +4.4 rORtg in 60 games with Robinson, Tony Parker and sharpshooter Steve Smith (who shot 47 percent from 3) while Duncan posted career bests in scoring volume and efficiency. These are commendable results, consistent with Duncan’s package; his isolation scoring and post-creation lifted San Antonio’s floor, even if his game didn’t scale too well.11

When Tony Parker and Manu Ginobili emerged in the middle of the aughts, Duncan slid into a costarring role before taking on a tertiary part in 2008. And the more the Spurs moved away from Duncan-ball, the higher their ceiling climbed. After leading San Antonio in offensive load from ’99-04, Duncan slid to fourth on the team in ’06 while struggling with nagging injuries like plantar fasciitis. Yet, the Spurs registered an impressive +4.8 rORtg when healthy that year (a figure that dropped to -1.4 in 17 games without Ginobili). At full-strength, the similarly constructed ’07 team finished with a +4.1 rORtg. Later, the Spurs offense jumped another level behind Parker, Ginobili and a collection of skilled role players, posting jaw-dropping full-strength ratings of +9.1 in 2012 and +7.6 in 2014.12 Duncan deserves credit for scaling down his isolation on these teams in exchange for valuable extra passes.

I’d be remiss not to acknowledge Popovich more, who, for my money, is the greatest coach in NBA history. He transitioned the Spurs from a defensively-oriented team that orbited around its twin-towers, to a perpetual motion, Euro-style offense built around perimeter players who could pass and shoot. This morphed into a brief offensive dynasty, peaking in 2014 with one of the greatest teams of all-time, unheard of for an ensemble production that lacked a troupe of stars. Popovich’s success on both sides of the ball does take some of the shine off of Duncan for me.

Duncan is one of the favorites of the plus-minus family. In every scaled season from 2001 to 2008, he falls in the 99th percentile historically, and each of his first 14 seasons is above the 95th percentile. He is the only other player besides Kevin Garnett with top-50 APM peaks on both sides of the ball. While his two-way value is excellent by any assessment — plus-minus, box stats or game-level regressions — teasing out his impact from Popovich’s is not trivial. Unlike a great teammate on the court, plus-minus data doesn’t “see” Pop’s value.

Duncan’s portability isn’t top-notch either; he’s savvy enough to scale down his offense (as he did in later years), although his limited passing prevents him from matching Garnett’s impact in a secondary role. His longevity was fantastic, tallying 17 All-Star seasons by my valuations, tied for tops in this series. He, KG and Wilt all have similar peaks and era-adjusted career value, and thus feel nearly interchangeable in these slots. So, while Garnett and him are neck and neck, if I were forced to choose, I’d oh-so-barely side with Duncan. (Are ties allowed?)

  1. In the ’98 playoffs, he effectively checked Jason Kidd for stretches. Yes, it’s difficult to believe, and one of the craziest matchups I remember seeing. Some other quirks from this era: 6-foot-6 Rick Fox guarded Duncan for a stretch during the 1999 playoffs and Kevin Garnett and Dirk Nowitzki both started at small forward next to two centers. Oh, how the league has changed.
  2. As a rookie, Duncan finished fifth in the DPOY voting with four first-place votes. His best finish was third; in 2001 he tallied 14 votes and in 2007, 15 first-place votes. Through the 2017 season, he is 16th all-time in DPOY Shares.
  3. I tracked about 1300 Duncan possessions in those two seasons and his error rate was just under 1 per 100.
  4. For comparison, Duncan’s strides were shorter than Garnett’s — there’s a similar play in Garnett’s profile where he takes three steps to slide down instead of Duncan’s five. Duncan arrives about a half-second slower than KG.
  5. Based on tracking, I estimate about 3 shots per 100 were of this nature, which means that about 12 to 15 percent of his field goal attempts came off putbacks like this.
  6. The second-best improvement belongs to the 2008 Celtics, who jumped 9 points in rDRtg. No other team in history is over 8.
  7. Data from NBA.com.
  8. In the chart below, “unique” seasons are the best five-year stretches without any overlapping seasons. For instance, the best stretch for San Antonio was from 1998-2002, thus the 1997-2001 stretch is excluded because it shares seasons with the ’98-02 period.
  9. Adjusting for opponent expected free throw and 3-point values, the Spurs dropped 5.4 points (from -8.5 to -3.1) on defense without Duncan in those 13 games.
  10. Under-discussed subplot from the ’01 playoffs: Anderson was the Spurs most valuable offensive player according to plus-minus, but was injured for the showdown with the Lakers. San Antonio posted an offensive rating of 90 during the series.
  11. Since Duncan and the 2003 Spurs are the subject of a case study in Thinking Basketball, I’ll point readers to Chapter 9 of the book for more on them.
  12. That 2012 offense is the 15th-best full-strength one of all time. Without Ginobili for 27 games, they were +4. Manu was second on the team in load alongside Parker from ’10-14, and both were viable candidates for this GOAT list.

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