Adding Jimmy Butler fundamentally changed who the Warriors were last season — the way they played, the heights they could aspire to, their chances of playing meaningful basketball deep into springtime once again. Losing Butler on Monday to a torn right ACL — a devastating blow that sapped every ounce of sweetness out of Golden State’s fourth consecutive double-digit win — fundamentally changes who the Warriors are this season, and threatens a devastating alteration to who they could conceivably still be in the “fading dynasty” stage of the Stephen Curry/Draymond Green/Steve Kerr era.

Let’s start with the obvious: It is extremely, extremely damaging to lose a player as good as Butler, whose teams have either outright won or been demonstrably better in his minutes in every season save the one where he was trying to force his way out of Minnesota.

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Even at age 36, a crisp 15 years and nearly 35,000 NBA minutes into his career, Butler remains one of the league’s best all-around players — a high-efficiency, low-mistake offensive connector; a versatile and disruptive defender; a high-IQ adaptor able to fit neatly into the flow when playing alongside Curry and scale up into a larger, more central role when Steph’s off the floor; a consistently high-floor contributor with few peers at his position.

Butler is second on the Warriors in scoring, third in assists and rebounds, and leads them in steals and total minutes played. There are four players in the NBA this season averaging at least 20 points, five rebounds, four assists and a steal per game while making at least half of their shots: Butler, perennial MVP favorite Nikola Jokić, and ascendant All-Star-caliber bigs Alperen Şengün and Jalen Johnson.

The advanced stats, as ever, love him: He’s been a top-15-to-20 player this season in the eyes of estimated plus-minus, LEBRON, DARKO, value over replacement player, player efficiency rating, win shares per 48 minutes, box plus-minus and regularized adjusted plus-minus, among other metrics. The Warriors have been 9.6 points per 100 possessions better with Butler on the court than off it this season, according to Cleaning the Glass; among players who’ve logged 1,000 minutes, that’s the 10th-largest on/off swing in the NBA.

Butler had averaged just under 22-5-5 on pristine .649 true shooting over the past month prior to exiting early against Miami. He was playing some of the best ball of his career, and with it, the Warriors had started to stabilize: Golden State has won four straight and 12 of its last 16, with the NBA’s second-best record and fifth-best net rating in that span.

During that period, the Warriors have outscored opponents by 8.4 points per 100 possessions with Butler on the floor, compared to a plus-4.4 net rating without him. That includes a mammoth plus-12.9 net rating in the 183 minutes that Butler played without Curry, continuing the trend that began last season of Golden State finally being able to not only survive non-Steph minutes, but sometimes actually build a lead while he rested. (Imagine that.)

Only one Warriors five-man lineup without Butler in it has played more than 20 minutes together this season; the quintet of Curry, Green, Gary Payton II, Brandin Podziemski and Moses Moody has been outscored by 13 points. That, um, will need to change — as will the general tenor of the non-Steph minutes, which, with Butler lost for the season, threaten to return to disaster time. The Warriors have been outscored by 3.9 points-per-100 this season with neither Curry nor Butler on the floor, posting a dismal non-garbage-time offensive rating of just 105.2 — several sub-basements below what the league-worst attack of the Tyrese Haliburton-less 10-34 Pacers has mustered over the course of this season.

Combine that with the degree to which Golden State had struggled to tread water in non-Jimmy minutes even with Steph on the floor — just plus-1.1 points-per-100 over nearly 500 minutes this season — and the Warriors have a pretty gnarly puzzle to solve over the second half of the season if they hope to have any chance of remaining in postseason position.

Golden State enters Tuesday’s game against the Toronto Raptors at 25-19, in eighth place in the Western Conference — in line for their third straight trip to the play-in tournament. With Butler in the fold and playing at an All-Star level, Kerr, general manager Mike Dunleavy Jr. and Co. could reasonably harbor hopes of erasing the two-game gap between them and the fifth-place Houston Rockets, putting themselves in position to not only avoid the play-in but potentially challenge for home-court advantage in the opening round of the playoffs. Now, though, the Warriors braintrust now has to consider whether it’s likelier that they rise or fall — they’re three games ahead of ninth-place Portland, five games up on the 10th-place Clippers, and 5.5 clear of 11th-place Memphis — and how their internal projections will inform their decision-making ahead of the Feb. 5 trade deadline.

Five days past the NBA’s most closely watched trade eligibility date, Jonathan Kuminga remains a member of the Warriors. Twenty-four hours ago, it seemed likely that Dunleavy would keep beating the bushes in search of a deal that could turn the out-of-favor 23-year-old into something, anything, that could improve the Warriors’ chances of making a deep playoff run. But with Golden State now in desperate need of a wing-sized person capable of putting the ball in the basket, even if it’s not in precisely the way Kerr prefers, and with the most frequently stated reason for shelving Kuminga — effectively, we can’t play three not-really-shooters who need the ball in their hands, and Jimmy and Draymond are better than Kuminga is — does that calculus change?

If and when Kerr turns back to Kuminga — which he didn’t on Monday, but which he said could happen in the days and weeks ahead — how might the fifth-year forward respond? It seems like an awful lot, asking someone who has essentially been out of the rotation for two months to suddenly start replicating the production of a top-20 player — especially considering lineups where he’s had to carry the offensive workload without Steph or Jimmy have gotten drilled over the past two seasons. If a reintroduced Kuminga struggles under these adverse conditions, does it become even more difficult to move him for a return of noteworthy value? And if he doesn’t — if he looks great — well, then what do you do with a guy you’ve signaled in every way possible that you’re ready to drive to the airport at the earliest opportunity, but who’s suddenly become a load-bearing column in your current build?

The $ 11 billion question hanging over all of this, in the hours after Butler’s grim diagnosis: Just what is that “current build,” now?

The premise behind the Butler trade and subsequent extension was clean, clear and evident to all who observed it. Golden State had lined up the contracts of Curry, Butler and Green to take aim at a title run in 2024-25 and 2025-26, with a possible third in 2026-27, when Green holds a $ 27.7 million player option. It was an unmistakable declaration of intent: As long as we have Steph playing LIKE THIS, we’re going to go for it.

And it worked, and it looked great … until it didn’t. The first run ended in the second round, after Steph hurt his hamstring against the Timberwolves; with Butler’s season now over, the second one appears to have ended before it could even get started. And now, the Warriors find themselves back where they were this time last year: with Curry still playing like this, but without a supporting cast commensurate with the frankly unbelievable level at which he continues to produce.

Maybe that gives the rest of Golden State’s roster short shrift. De’Anthony Melton is finally healthy again and playing great. Al Horford’s starting to show signs of coming around. Podziemski’s in the midst of his best run of play of the season. Moody and Buddy Hield are shooting better than 40% from 3-point land over the last month. Maybe they keep rolling, and Kerr’s able to find enough contributions from elsewhere — from rookie Will Richard, from Quinten Post, from Trayce Jackson-Davis, and on, and on — to keep the Warriors in the fight, where they’re forever one Curry flurry from delivering a knockout blow.

And maybe the injury doesn’t necessarily preclude one last big comeback run. The average return-to-play following an ACL tear is about 11 months, according to Jeff Stotts of In Street Clothes; that would put Butler’s return somewhere around Christmas, meaning he’d miss roughly the first quarter of the 2026-27 season, giving Golden State a lot of runway to get up to full strength before mid-April. Maybe there are still two real bites at the apple here.

Maybe, though, Butler’s injury shakes the Warriors’ faith in the viability of that timeline — in the likelihood that, 14 months from now, a core of a 39-year-old Curry, a 37-year-old Green and a 37-year-old, post-ACL-reconstruction Butler will be good enough to win in the playoffs. If Dunleavy and Co. arrive at that conclusion, they’ll have to decide whether they’re comfortable continuing to ride what they’ve got into the sunset — appreciating that time comes for us all, that best-laid plans sometimes go awry, and that it’s worth allowing the Steph-Draymond-Jimmy core to run its course — or if it’s time to make even more drastic changes to the roster, in service of seeding the ground for the next era of Warriors basketball, whenever that might start.

The former path would be perfectly respectable, if not downright honorable. In a world that’s seen the Warriors try to pull off the two timelines plan and let Klay Thompson walk, though, the latter can’t be ruled out. I don’t think that means they’re going to trade Steph in the middle of the night. (Although, y’know: Luka.) I do think, though, it means that just about anything else could be on the table, one fundamental change begetting another.