Stephen Curry’s latest ankle injury reinforces how his health will determine much of what happens this NBA season. (Kyle Terada/USA Today)

So much has changed for the Golden State Warriors, and the NBA as a whole, since the franchise surged overnight into a championship contender at the start of the 2014-15 season. The Warriors have won two of the past three titles, and are the favorites to win a third. Kevin Durant’s arrival gave Golden State four of the 15 best players in the league — an unprecedented amount of talent in its prime on one team in the sport’s modern era. As a result, a handful of teams has scrambled to try to catch the Warriors, and another handful has decided instead to chase the future.

But for everything that has changed, one thing hasn’t: Golden State — and, by extension, this entire league — hinges on the health of Stephen Curry’s ankles.

Golden State rallied from a double-digit deficit in the fourth quarter Thursday night to beat the San Antonio Spurs, but everyone inside the organization and out was focused on Curry’s right ankle, which acted up for the fourth time this season —  and the second time within a week.

“He won’t play tomorrow,” Warriors Coach Steve Kerr told reporters, referring to Friday night’s game in Portland, “and we’ll just take it day-by-day.”

The Warriors called Curry’s injury a “tweak,” the same word used to describe the injury he suffered in last Friday’s victory in Atlanta. Curry left the arena Thursday night wearing regular shoes, a positive sign about his ability to get back on the court soon.

But there’s a reason Draymond Green described seeing Curry injure his ankles as “kind of a ‘hold your breath’ type of moment.” The Warriors are only the Warriors when Curry is healthy and operating at peak efficiency.

With Curry on the floor, the Warriors are scoring 120.7 points per 100 possessions, according to NBA.com’s stats page, an absurd number that is nearly seven points higher than the team’s league-leading 113.9 points per 100 possessions — a mark that would make the Warriors the greatest offense in NBA history if it holds up. With Curry on the bench, Golden State has been 8.8 points per 100 possessions worse than it is with him on the court.

The Warriors know they need to get to the postseason healthy — and that, if they do, they will be overwhelming favorites to win a third championship in four years, and a second in a row. Both publicly and privately, they have dismissed the importance of getting the top seed in the Western Conference. They are not concerned about the potential of having to travel to Houston at the start of what everyone hopes is the conference finals, a series that has — at least on paper — the potential to be an all-time classic, and one that some even think the Warriors could lose.

If the Warriors are not healthy — and, specifically, if Curry is not — then the door is opened for others to spoil their fun. This is precisely the reason Rockets General Manager Daryl Morey swung for the fences this past summer by trading for Chris Paul and making several savvy moves, including grabbing veteran forwards P.J. Tucker and Luc Mbah a Moute to give Houston a plethora of wings to throw at Golden State’s scorers.

All it takes is one false step, one piece of misfortune, to break the race for the 2018 NBA title wide open. That’s something the Warriors learned the hard way: In 2016, Curry’s ankle and knee injuries left them vulnerable, and the Cleveland Cavaliers were able to exploit that in the Finals to complete one of the great comebacks in NBA history.

That was why the Warriors went after Kevin Durant that summer, to ensure they would have another all-time great player to lean on if Curry went down again. And, right on cue, Durant scored 14 straight points, and 15 of Golden State’s final 17, on Thursday to give the Warriors a seventh straight win.

“We still have three all-stars when Steph goes down,” Kerr said. “We still have a lot of talent.”

Of course they do. But with Curry, Golden State is a swaggering, shot-making juggernaut, one that seems unstoppable whenever this team ramps it up to 11 — just as it did during last year’s playoffs, when it won 15 straight games and went 16-1 to claim that second title. But without him, the Warriors become a merely great team, and one that would — at a minimum — be given a hell of a run by the Rockets and some of the league’s other elite teams.

So when the Warriors left for Portland early Friday morning, Curry stayed behind to rest and rehabilitate his injured ankle.

It’s a familiar position for this Warriors team, but one that, after the years Curry spent dealing with one of these sprains after another, both he and the Warriors had hoped was in the past. Now, four sprains/tweaks/instances later, it is again very much in the present.

Curry makes the Warriors a special team. Now they have to hope his ankles will allow them to be that special team again when it matters.

Read more: 

25 players to watch in the NCAA tournament if you’re an NBA fan

Kelly Oubre Jr. joins NBA players sharing mental health struggles: ‘We’re normal people, man’

LeBron James thinks his game is at ‘an all-time high.’ Based on his age, he may be right.

Now LeBron James is being wooed by billboards to join the Los Angeles Lakers

Psst, tanking NBA teams: Here are a few lineup tweaks that can get you more losses