Some of the NBA’s more casual fans may have been surprised to learn Wednesday that, on the final day of the league’s regular season, Russell Westbrook was extremely close to averaging a triple-double — for the second straight season. The Oklahoma City Thunder guard got there, snaring more than the 16 rebounds he needed in a win over the Grizzlies to become the first NBA player to average a triple-double in multiple seasons, but his pursuit of the feat this time was accompanied by distinctly less hullabaloo than when he accomplished it in the 2016-17 campaign.

That raises the question of why the NBA community seemed to care so much less this season about a statistical performance that caused so much excitement just 12 months ago. Here are some likely causes of the apparent ennui.

Been there, cheered for that

The simplest explanation is often the best one, and in this case, when Westbrook did it last season, he became only the second NBA player ever to do so and the first in a whopping 55 years. Now Westbrook has become the first player to do so since … last year.

The first season-long triple-double was pulled off by Oscar Robertson in 1961-62, and the Hall of Famer was interviewed frequently last season as Westbrook got ever closer to equaling his feat. That added a compelling layer of historical significance to the OKC star’s quest, and it’s worth noting that we’ve seen a lot less of the legendary “Big O” this time around.

Fewer heroics

Westbrook’s quest got off to a bang last season, as he posted a 51-13-10 line in the Thunder’s second game, notching the NBA’s first 50-point triple-double in 41 years. He would go on to have two more such performances, including a record 57-point triple-double in late March while leading OKC back from a 21-point deficit against the Magic. That outing came one game after Westbrook scored 12 points in the final 3:22 as his team closed a matchup with the Mavericks on a 14-0 run, for a thrilling one-point win.

That season saw Westbrook break Robertson’s mark for most triple-doubles in a season, finishing with 42, and creating a months-long drumbeat for his chase of a fabled achievement. By the time he got No. 42, he’d already assured himself the season-long mark, having begun averaging a triple-double by late November, and he ended up leading the league in scoring at 31.6 points per game, with 10.7 rebounds and 10.4 assists.

Westbrook put up 26 triple-doubles this season, still enough to easily lead the NBA but notably fewer than last year, and his per-game marks were lower, as well, at 25.4 points, 10.1 rebounds and 10.3 assists. For almost the entire season, he was not averaging a triple-double, causing his quest for a repeat to fly under the radar, to a large degree.

The lesser numbers had much to do with a beefed-up supporting cast, as Paul George and Carmelo Anthony were brought in before the season and Westbrook took fewer shots while posting a much lower usage rate (albeit a still very high one by leaguewide standards; his 41.7 mark in 2016-17 was just completely astounding). By contrast, having lost superstar forward Kevin Durant to the rival Warriors in the previous offseason, big things were not expected from the 2016-17 Thunder, and Westbrook’s exploits created a sense that he was more or less strapping the team to his back on the way to a sixth-place finish in the ultracompetitive Western Conference.

Buyer’s remorse

Last season, a debate raged over who was more deserving of the MVP award: Westbrook or James Harden. Advocates of the Rockets guard pointed to his far greater efficiency, equally gaudy stats by at least some measures and a significantly better record with his own less-than-stellar supporting cast.

The Thunder star got that award, of course, as his stacking of triple-doubles on top of huge scoring performances created an irresistible narrative. This season, though, Harden has more or less justified his backers’ belief, leading Houston to the best record in the NBA — albeit with help from a key new addition, Chris Paul — while Westbrook’s revamped Thunder have more or less stayed in place.

OKC won just one more game than last year, although it moved up to the fourth seed in the West playoffs. This time around, there has been no talk whatsoever of Westbrook as an MVP candidate, let alone a front-runner, and in some respects, it feels like there has been a bit of a hangover from last season’s giddiness over the triple-double outbursts.

Just a stat-padder?

There certainly seems to have been more scrutiny over the validity of Westbrook’s triple-doubles, as accusations of stat-padding that started last season, particularly with regard to his rebounding numbers, have followed him all the way to Wednesday, when he mounted a defense of his style of play before grabbing 20 boards in 37 minutes of play.

“A lot people make jokes about whatever, stat-padding or going to get rebounds,” Westbrook said before taking on the Grizzlies (via ESPN). “If people could get 20 rebounds every night, they would. If people could get 15 rebounds, they would. People that’s talking or saying whatever they need to say, they should try doing it and see how hard it is.”

Intentionally or not, Anthony gave fodder to his teammate’s naysayers by claiming that Westbrook “steals rebounds sometimes.” He added, though, that “any time you can have a guard like that to come back and rebound the way he does, because we want to push the break … a lot of good things happen from that.”

“Since everybody wants to be talking, I’m tired of hearing the same old rebound this, stealing rebounds, all this s—,” Westbrook defiantly added. “I take pride in what I do. I come out and play, and I get the ball faster than someone else gets to it. That’s what it is. If you don’t want it, I’m gonna get it. Simple as that.”

As mentioned, the distinct lack of excitement over Westbrook’s second season-long triple-double could be just as simple as having just seen it happen already, but there are likely other factors in play, as well. The good news for Westbrook is that, with the NBA playoffs upon us, he now has a chance to create a much more compelling postseason narrative than last year, when his Thunder won just one first-round game — while getting quickly bounced by Harden’s Rockets.

Read more from The Post: