This is why it matters that Portland got Oklahoma City twice without Kevin Durant — including a game the Thunder blew thanks to a dumb technical from Russell Westbrook and an apparent teamwide obliviousness concerning Damian Lillard’s most famous clutch shot.

This is why it matters that Lillard went berserk in San Antonio, salvaging an improbable triple-overtime win on the road.

This is why it matters, sadly for the Trail Blazers, that a lucky last-second bounce helped the sorry Celtics steal a win in Portland last night.

In the Western Conference, every game matters. Bank 31 wins in 44 games, and you could still be one major injury away from the playoff math getting uncomfortably tight.

Portland should still make the playoffs, even if LaMarcus Aldridge’s recovery from a thumb sprain stretches to the full eight weeks — a span that would cost him 23 or 24 games. The Blazers are five games up on Phoenix in the loss column, and eight games up on Oklahoma City for the lead in the Northwest Division. (We will discuss the stupidity of the phrase “Northwest Division” shortly.)

That’s a big cushion in what looks to be a nine-team race, with the Pelicans clinging to life by Pierre’s giant beak. But it’s not an insurmountable gap for the Suns and the Thunder. Aldridge is Portland’s best all-around player, and the Blazers’ schedule, second-easiest so far among Western Conference teams, is about to toughen up. Portland hosts Washington on Saturday before coming East for a four-game trip that includes visits to the rising Cavs, the unbeatable Hawks, and the frisky Bucks.

The Blazers’ next dozen games come against Western Conference teams, including eight against the other playoff contenders. That takes Portland to about March 7, the earliest range for Aldridge’s return. If Portland scraps to a 9-8 record in those 17 games, it will sit at 40-21, on pace for 53 or 54 wins — comfortably in the playoffs.

But if the damage is just a hair worse, Portland’s projected win total dips toward 50 flat — the official danger zone in the Western Conference bloodbath. And the pace of Aldridge’s recovery could prove huge. Portland speeds through seven games in 11 days, from March 11 to March 21, including five straight on the road. Aldridge could miss all seven if his recovery stretches to the full eight-week range. If he misses a full two dozen games, hanging in at .500 still inches the Blazers down toward a projected win total of 52. If they fall apart as his absence lingers, the math gets uglier.

Most analytics guys I spoke to over the last 24 hours have this injury costing the Blazers between three and five wins — not quite enough to knock them out of the postseason. But some anxiety is warranted. The Blazers’ offense has fallen apart with Aldridge on the bench this season, and just about every rotation player shoots better when he’s on the floor, per NBA.com. Aldridge missed two chunks of games in the middle of last season. Portland went 7-5 over those 12 games by going small, with Dorell Wright starting at power forward, and replacing Aldridge’s midrange game with a hail of 3-pointers. Portland’s “flow” offense has something of a plug-and-play quality to it, though we’ll have to see how the team fares with some unusual big-man combinations. Last season’s survival is encouraging on the surface.

But Portland started 5-1 without Aldridge before tailing off as the opposition got tougher. Its defense sprung major leaks after a strong start, and the team could not survive on the glass — a major Portland strength when the Blazers are whole. Their defense has actually been better with Aldridge on the bench this season, but the evidence suggests that will not persist when those non-Aldridge minutes come against opposing starters on good teams.

Last season’s Blazers were also basically healthy outside of Aldridge. These Blazers are not, and they are getting dangerously thin across almost all positions. They are already without both mascot-abuser Robin Lopez and Joel Freeland up front, and GM Neil Olshey said on Thursday that both could remain out until the All-Star break. Nicolas Batum has been a shell of himself all season, save for a breakout game against Phoenix on Wednesday, and he reaggravated an injury to his right wrist — his shooting hand — during Thursday’s loss to Boston.

The Blazers’ health issues may have reached a tipping point at which so many players are hurt that the latest and most serious injury to Aldridge could have an outsize impact. The Blazers could make a trade, and they’ve sat on their 2015 first-round pick as a bunch of the West’s top nine — Oklahoma City, Dallas, Memphis, and Phoenix — flipped first-rounders for some present-day help.

Portland was a decent bet to make that kind of deal even before Aldridge’s injury, though the need for a wing player like Wilson Chandler is probably more urgent given Batum’s shaky play and Terry Stotts’s lack of trust in the C.J. McCollum–Allen Crabbe–Will Barton bench mob. Olshey said Thursday that Aldridge’s injury would not force him into a panic trade for a big man — that Portland would still approach the trade deadline with its playoff rotation in mind, and not its immediate survival.

That makes sense. At full health, Aldridge, Lopez, and Zombie Chris Kaman can soak up almost all of Portland’s big-man minutes. Flipping a first-rounder and two midsize salaries for a player who might not contribute much in the postseason is painful. Portland has enough of a head start that Olshey can watch how the team fares without Aldridge and pivot his focus only if Portland’s front-line issues prove so catastrophic that he must act immediately.

The cheapo buyout market for big men is thin, and Portland has a full 15-man roster. No one knows if Emeka Okafor can play, or even if he wants to, and the Celtics appear reluctant for now to buy out Brandon Bass. Any Western Conference playoff team with a tradable rotation big — Phoenix with Miles Plumlee, for instance — will be hesitant to throw Portland a life raft. Sexier Eastern Conference names like David West and Kevin Garnett earn enough salary that it would be difficult for Portland to cobble together matching money.

The Lakers have Ed Davis and Jordan Hill on semi-expiring contracts. Enes Kanter’s future in Utah is unclear, though the idea that Utah should just shove him out the door to make way for the French Rejection is a little premature. Olshey might sniff around the possibility of nabbing Jason Thompson from Sacramento on the cheap, though Portland has already dealt away the rights to its second-round picks every year through 2018. Taking on Thompson’s salary for next season would also eat away at Portland’s potential cap room, which could matter in the nightmare scenario that Aldridge bolts in free agency.

Thomas Robinson and Meyers Leonard have both shown flashes during their on-again, off-again rotation appearances, and Leonard especially is clearly an improved player on both ends — popping 3s, hitting some floaters, and looking less lost on defense. Portland has dusted off Victor Claver as a Dorell Wright–esque small-ball power forward in the last week, but it’s unclear if any of these guys are ready for major minutes. We’ll find out.

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But again: Portland at full strength needs a boost on the wing, and not up front. The best bet for now is that the Blazers ride this out and keep their eye on the big picture. This team at full health is absolutely a fringe title contender. These Blazers are polished, and icy cool. They know exactly what they want to do on both ends of the floor, and they’ve mastered Stotts’s conservative defensive scheme after about 150 games of executing it over the last two seasons. The Blazers have been a top-five defense almost all season, and spent most of the last three weeks holding the no. 2 spot in points allowed per possession — trailing just the ridiculous Warriors. A Blazers team that can defend like that is scary. But they probably can’t defend like that without Aldridge.

What the Blazers Will Miss

He has developed into the rare big man who can do a little bit of everything on defense. He’s tall enough, with long arms and a tough disposition, to battle behemoths in the post and to protect the basket. Stick him against Memphis, and Aldridge can manage fine against Marc Gasol or Zach Randolph.

He’s also quick enough to scurry around against jump-shooting power forwards:

He can hedge and recover against Dirk Nowitzki and Ryan Anderson types. Aldridge’s defense is a big reason the Blazers are essentially matchup-proof — a hugely valuable trait in the playoffs, especially in the West, where matchups trump seedings. (On a side note, this same kind of versatility is part of what makes Tiago Splitter so valuable to the Spurs.) He might not be able to handle a true small-ball 4 like Kevin Durant, but he can give it a go, and if he can’t manage, the Blazers are fine having him track a lesser wing threat like Anthony Morrow. Want to switch pick-and-rolls, leaving Aldridge to defend a point guard for the last eight seconds of the shot clock? He’s among the best at that, too.

His killer jump shot has the reverse effect on the other end of the floor: Opponents ditch their foundational game plans to account for Aldridge. If your starting power forward is too small to check him in the post, you have to slink into plan B — swapping your center onto him, or rejiggering your starting lineup to add more size. Houston mothballed the Omer Asik–Dwight Howard pairing last season, only to break it out again when Terrence Jones proved incapable of dealing with Aldridge.

That’s in part because Aldridge has remade himself into something more than a jump-shooter. He’ll back down smaller defenders if he senses a matchup advantage, and he has a nifty off-the-dribble game if he catches the ball in open space:

It has been fashionable to suggest that opponents overreact to the threat of Aldridge’s midrange jumper. The midranger is, after all, the least efficient shot in basketball. Aldridge has hit about 45 percent of his open 2-point jumpers over the last two seasons, per SportVU data. That’s quite nice, but it still amounts to less than one point per possession over the long haul. Is that really so devastating that teams should double him in the post and rotate a third defender all the way across the floor to snuff out his jumper — a rotation that leaves Portland’s killer 3-point shooters open?

In a vacuum, the answer is probably no. But a basketball game is not a lab environment. Aldridge will bulldoze his way to the rim just enough to keep defenses honest, and turn some of those 45 percent jumpers into close shots and free throws. And coaches, even the very best ones, just haven’t had it in them to leave Aldridge alone when he gets rolling — to deal with him one-on-one in the post, or give him those open pick-and-pop jumpers. It just isn’t in coach DNA.

The best teams can strike a balance at which they help just enough, without over-helping. But that’s a hard equilibrium to find, especially when you’re adapting on the fly in the hothouse of the playoffs. Aldridge has made it a tad harder on defenses this year by stepping out for more 3s when they come from the natural flow of his game — in transition, and on pick-and-pops that occur high enough on the floor that he just kind of fades naturally beyond the arc. He has canned 21 3s this season after making just 24 combined over his first eight years in the league. This dude … man, he’s good.

It helps that the Blazers are in the Northwest Division, which consists of Portland, Oklahoma City, and three bad teams. The winner of each division is guaranteed a top-four seed regardless of record. There is a universe in which it is possible for a division winner to finish with the ninth-best record in its conference and still make the playoffs. That isn’t in play this season, since Portland will have finished with a better record than at least Oklahoma City if the Blazers hang on in the Northwest.

But the top-four guarantee matters. It doesn’t matter as much as it did before a rule change in 2007, since the top-four guarantee does not come with home-court advantage. If the Blazers face an opponent with a better record in the 4-5 series, they would start on the road.

Still: The Blazers could finish with the seventh- or even eighth-best record in the conference, and still lock in at no. 4 for seeding purposes. That may not be vital this season, since all eight Western Conference playoff teams might have plausible championship hopes. Seedings are irrelevant, the thinking goes.

That’s only sort of true. Think about a scenario in which Phoenix passes Portland, but the Blazers win the Northwest with the eighth-best record in the West. (The Thunder would miss the postseason in this scenario, obviously.) If the league slotted teams by record, the Blazers would get the no. 8 seed — and a first-round matchup with the juggernaut Warriors. But with the pathetic Northwest in their pocket, the Blazers would instead land in a 4-5 seed against a Dallas/Memphis/Houston type.

This scenario is like downgrading from one video game boss to another, but even slight downgrades matter. It’s true that to win the West, you’re going to have beat the very best teams at some point. But every round you delay facing those teams is a round in which they might suffer some injury, upset, or other sad twist of fate.

Most of these nightmare seeding scenarios in which weak division winners get some undeserved advantage never play out. But every season, even into April, they are sitting there as possibilities. They are in play. We go through the complex web of tiebreakers, suss out the rules, and post long strings of tweets explaining each potential path.

It’s dumb. Divisions are dumb. They are needless complications. They serve no real purpose anymore, especially since teams play almost every other team in their conference four times apiece. Just get rid of them.

That’s a separate discussion. It will be fascinating to see how the Blazers fare with their roster in tatters, and after years of good health luck in the aftermath of the Greg Oden–Brandon Roy era. This is a really, really good team, and it would be sad to see the Blazers tailspin. They have the chops to get through it. Let’s hope they do.