* Tonight on TNT: Thunder vs. Spurs, 9:30 ET

The Oklahoma City Thunder have been a bit of a surprise this season. Since losing their first four games, they’ve been near the top of the Western Conference, building a 25-15 record behind the league’s best defense. They’ve done so despite the absence of Andre Roberson, who made a huge difference for them defensively last season.

Russell Westbrook has yielded some of the offense to Paul George, who’s having a career year. Steven Adams has been one of the league’s best two-way centers, and the supporting cast has done enough behind the three stars.

The Thunder have wins over five of the other other teams currently in playoff position in the conference, but overall, they’ve played the West’s easiest schedule thus far. One of the teams they’ve yet to face is the San Antonio Spurs, who they play twice in the next three days, in San Antonio on Thursday (9:30 p.m. ET, TNT) and in Oklahoma City on Saturday (8 p.m. ET, NBA TV).

As good as the Thunder have been, there’s still room for improvement. Here’s one number to know about the 2018-19 Thunder as the head into an important home-and-home series …

THE STAT

The Thunder have an effective field goal percentage of just 45 percent on shots from outside the paint.

THE CONTEXT

That’s the lowest mark in the league.

We can’t say that the Thunder have been the worst shooting team from outside the paint. The Atlanta Hawks have made a lower percentage of their shots from the outside (33.5 percent) than the Thunder (34.3 percent).

But the Hawks have taken a greater percentage of their jump shots from beyond the arc. Atlanta’s ratio of 3-point attempts to mid-range attempts is 4.3, the third highest in the league. The Thunder’s ratio is 1.9, the league’s 10th lowest rate and less than half that of the Hawks. (The league average is 2.2). So Atlanta has gotten more value out of their outside shots.

The Thunder rank 24th in effective field goal percentage overall. They’ve taken 38 percent of their shots, the league’s fourth-highest rate, in the restricted area, where every team shoots best (and most effectively, even when taking the value of 3-pointers into account).

Their ability to get to the basket helps make up for the poor shooting from the outside. Steven Adams (10.2) and Russell Westbrook (9.6) both rank in the top 15 in points per game in the restricted area.

The Thunder have also been better than the league average in regard to taking care of the ball (ranking 12th in turnover percentage) and getting to the free throw line (ranking 13th in FTA/FGA). They rank second in offensive rebounding percentage, having grabbed more than 30 percent of available offensive boards.

The Thunder’s No. 1 ranked defense also produces offense. They lead the league in opponent turnover percentage (17.3 per 100 possessions) and rank second with 20.5 *points per game off turnovers. No team has taken a greater percentage of its shots in the first 12 seconds of the shot clock.

* Points off turnovers is a flawed statistic because it doesn’t distinguish between live-ball and dead-ball turnovers. But the Thunder lead the league in opponent live-ball turnovers (recorded as steals) by a pretty wide margin.

But the outside shooting is an issue. Shooting is the most important thing in the NBA and league-wide, offensive efficiency correlates stronger with effective field goal percentage from outside the paint than it does with field goal percentage in the paint. The Thunder are actually the only team that ranks in the bottom 10 in effective field goal percentage from outside the paint and has a winning record.

Through Wednesday, the Thunder rank 20th offensively, having scored 107.6 points per 100 possessions. Only three teams — the Cavs, Bulls and Timberwolves — have seen a bigger drop in efficiency from last season, when the Thunder ranked seventh offensively (109.9 points scored per 100 possessions). They weren’t a very good shooting team from the outside last season, but they weren’t as bad as they are this year. They ranked 25th in effective field goal percentage from outside the paint (47.3 percent) in 2017-18.

The Thunder have seven players who have taken at least 75 shots from outside the paint, and only two of the seven — Paul George and Jerami Grant — have an effective field goal percentage from the outside better than the league average (49.0 percent).

Dennis Schroder has never been a very effective shooter from the outside. Terrance Ferguson isn’t much more of a threat from the outside than Roberson was the last couple of seasons. Patrick Patterson has been a disappointment since coming from Toronto in 2017, and Alex Abrines has seen a big drop in 3-point percentage from last season.

Of course, after George, the Thunder player who has taken the most shots from outside the paint is Westbrook, who ranks 53rd in mid-range field goal percentage (33.3 percent) among 54 players with at least 100 mid-range attempts and 165th in 3-point percentage (23.5 percent) among 165 players with at least 100 3-point attempts.

Westbrook has never been a good shooter from the outside, but this has been the worst jump-shooting season of his career. The mid-range field goal percentage is the worst of his career, while the 3-point percentage is the worst since his second season (when he took far fewer threes).

Westbrook has cut down on pull-up jumpers, averaging 8.7 per game (eighth most in the league), down from 9.7 last season and 12.4 two seasons ago. According to Second Spectrum tracking, 19 percent of his jumpers have been off the catch, and that’s the highest rate for him in the six years of tracking data (up from 11 percent last season). But he has shot worse (and less effectively) on catch-and-shoot jumpers (16-for-67, 24 percent, effective FG% of 34 percent) than he has on pull-up jumpers (90-for-279, 32 percent, 36 percent).

The 2016-17 Kia MVP is averaging a triple-double for the third straight season and doing so with his lowest usage rate (30.4 percent) since his second year in the league. The Thunder offense has been 12.1 points per 100 possessions better with him on the floor (scoring 111.1 per 100) than with him off the floor (102.1).

But you wonder how good it could be (and how high this team’s ceiling would be) if he wasn’t, essentially, the league’s worst high-volume jump-shooter.

THUNDER BASICS

Pace: 103.8 (4)

OffRtg: 107.6 (20)

DefRtg: 102.2 (1)

NetRtg: +5.4 (3)

THUNDER LINKS

Team: Game log | Traditional | Advanced splits | Lineups

Player Traditional | On-off court | Shot locations | Clutch

THUNDER NOTES – GENERAL

1. The Thunder are 25-15 with the point differential (plus-5.6 per game, best in the Western Conference) of a team that’s 28-12.
2. They’re 8-13 in games that were within five points in the last five minutes. That’s the league’s fourth worst mark, but also means that only two of their losses have not been within five in the last five. Every other team has at least four non-clutch losses.
3. The have been the league’s best team in the last two minutes of the first three quarters, outscoring their opponents by 18 points per 48 in the last two minutes of quarters 1-3.

THUNDER NOTES – OFFENSE

1. The Thunder have scored 2.3 fewer points per 100 possessions than they did last season. Only the Cavs, Bulls and Timberwolves have seen a bigger drop in offensive efficiency.
2. They’re one of two teams (New York is the other) that rank in the bottom 10 in both 3-point percentage (32.3 percent – 30th) and the percentage of their shots that have come from 3-point range (32.1 percent – 23rd).
3. Rank in the bottom five in assist percentage (they’ve assisted on less than 53 percent of their field goals) for the third straight season (and for the sixth time in the last eight seasons).

THUNDER NOTES – DEFENSE

1. Thunder opponents have taken 70 percent of their shots from the restricted area or 3-point range, higher than the league average (68 percent). But they rank in the top six in opponent field goal percentage in both the restricted area (sixth) and from mid-range (third), and they rank third in opponent 3-point percentage.
2. Their opponents have taken 34.7 percent of their shots from 3-point range. That’s only the 13th lowest opponent rate, but it’s down from 36.4 percent (third highest rate) last season. Only Detroit and the Clippers have seen a bigger drop in the percentage of their opponents’ shots that have come from 3-point range (with the league average increasing for the eighth straight season).
3. Their opponent turnover rate of 17.3 per 100 possessions is the highest of the last four seasons.

THUNDER NOTES – LINEUPS

1. The Thunder starting lineup — Westbrook, Ferguson, George, Grant and Adams — has outscored its opponents by 17 points per 100 possessions in its 336 minutes. That’s the best mark among 22 lineups that have played at least 200 minutes together. Its cumulative plus-minutes of plus-121 is the highest in the league by a wide margin (next highest is plus-80).
2. Westbrook, George and Adams have played 28.7 minutes per game together, most among 248 three-man combinations that have played in at least 20 games.
3. The Thunder have been 16.6 points per 100 possessions better with George on the floor (plus-9.5) than with him off the floor (minus-7.1). That is the third biggest on-off-court NetRtg differential among 122 players who have played at least 1,000 minutes this season. Steven Adams (15.2 points per 100 possessions) has the fifth biggest differential in that same group.

THUNDER NOTES – INDIVIDUAL

1. Now in his sixth season in the league, Steven Adams has seen an increase in scoring every year, from 3.3 points per game as a rookie to 15.4 this season.
2. Terrance Ferguson has a usage rate of just 9.7 percent, the second lowest rate among 218 players who have averaged at least 20 minutes in 20 games or more.
3. Paul George is registering career highs in points per game (26.8), rebounds per game (8.0), steals per game (2.2), and assist-turnover ratio (1.45).
4. Jerami Grant has taken 64 percent (75/118) of his 3-pointers from the corners. That’s the second-highest rate (behind that of P.J. Tucker) among 165 players with at least 100 3-point attempts, though Grant hasn’t shot much better on corner 3-pointers (36 percent) than he has on above-the-break 3-pointers (34.9 percent).
5. Dennis Schroder‘s effective field goal percentage of 45.3 percent is the lowest mark since his rookie season. He has taken 29 percent of his shots in the restricted area. That’s the lowest mark of his career and down from 33 percent last season.
6. Russell Westbrook leads the league in assists (10.3 per game), potential assists (19.4 per game) and assist points created (24.1 per game). He has twice as many triple-doubles (12) as any other player.
7. Westbrook has averaged 3.8 deflections per game, most among players who have played at least 20 games. George ranks third with 3.6 deflections per game.

* * *

John Schuhmann is a senior stats analyst for NBA.com. You can e-mail him here, find his archive here and follow him on Twitter.

The views on this page do not necessarily reflect the views of the NBA, its clubs or Turner Broadcasting.