The myth of the Diamondbacks September ‘meltdown’

Now, a heavily upvoted shitpost from the Diamondbacks subreddit, and a Tweet by one of the most toxic members of fandom may not seem worth bothering about. And they probably are not. But it does reflect a general feeling that September is the cruelest month for Arizona fans. It is true that this is the fourth consecutive season where the team could be seen as imploding. There was the "backing into the post-season" meme from 2023, missing out by a narrow margin in 2024 and 2025, and while the story of this year has yet to be completed, at the time of writing the team is on the outside of the NL playoff picture. Never mind that their record would be winning two of the three divisions in the AL…

So, first stop. Is there any truth to the perception?

The team's performance in September over the past few years is not particularly better or worse than their performance the rest of the year. Indeed, the last time the D-backs had any kind of losing record in September was in 2022. Here's their performance by each calendar month since the beginning of the 2023 season:

The overall win percentage in that time is .521. Based on that, over the 3.5 seasons and 92 September games, you would expect their record in the month to be 48-44. It is actually… 47-45. If that's the "choking" demanded for the narrative, it's an underwhelming one. Now, I also hear, "The meltdown is when they need to win the last few games to make the wildcard they lose." So let's take a look at each recent season specifically, and see what actually happened.

2023 . Well, the above doesn't exactly support the idea of a meltdown, does it? On September 13, Arizona had just a 30.7% chance of making the post-season. But they were about to go on an 8-2 run which included sweeps against both the Cubs and Giants. The former was particularly huge. They came in to Chase Field on September 15, with a 2.5 game lead over the D-backs, and left three days later, behind Arizona and broken. Including that series, Chicago went 5-10 the rest of the way, and their odds cratered from 58% to zero in five days. Now that's what I call a genuine September meltdown. Losing the last four games, as the D-backs did? Irrelevant, as the subsequent playoffs proved.

2024 . This is the season where I would say there is the best case for a meltdown, and it's likely where the myth began. Though September as a whole was hardly a disaster, Arizona going 13-13. That, however, perhaps felt like a meltdown after the Diamondbacks went a stellar 35-17 in July and August. With seven games to go, the D-backs were three clear of the Braves. However, they'd lost the tie-breaker. Arizona went 2-5, while the Braves went 5-2, and the rest is history. But four of those games were against the Padres and Brewers , who were ahead of us in the standings. It included a loss by the odd run in nineteen in Milwaukee . A win there and the meltdown myth never gets started. That's the margin we're talking about here. Maybe we should be blaming the team which started 4-7 that year, not the one which finished 6-5.

2025 . For there to be a "meltdown" in September, I'd say there has to be a significant chance of success there to begin with. But the highest chance of the D-backs making the post-season that month was only 12.3%. The last day it was even twenty percent – still an outside shot – was back on July 19. Sure, as in 2023, they finished the year on a losing streak: five games this time. But also as there, that ignores the good run the Diamondbacks went on immediately before that, winning seven of nine. They'd have needed to go 4-1 thereafter to reach the playoffs, for an overall 11-3 record over the last couple of weeks. Not doing so, going "only" 7-7, is hardly a meltdown.

What I think is interesting is why some people choose to think the D-backs collapse, when the facts really don't particularly support that as a narrative. I think part of it is actually a back-handed compliment, in that this is the first time, literally in a generation, where the D-backs have been consistently competitive for several years in a row. Put it this way: nobody cares very much right now about September meltdowns over at Purple Row , despite the Rockies playing 42 points worse after August 31. Below, you'll see the team's winning percentage through 136 games, which is there or thereabouts around the end of August (save for 2020, when I used the number through 35 games).

The 2023-26 run is the first time the Diamondbacks has been above .450 (the line highlighted above), through that point in the season, for five consecutive seasons since 2003. It's the first time in over twenty years where Arizona have had four seasons in a row with meaningful baseball in the second half of this month. We're not used to having September baseball that matters . Or, at least, it seems to. The reality, of course, is that wins and losses count exactly the same. If you're looking for a reason why we "backed into the playoffs" in 2023, the 8-16 record of the D-backs in July is a far bigger explanation than anything in September.

Maybe fans remember failure better than success? Just ask Byung-Hyun Kim. Or this season, where we've had perpetual complaints about D-backs' LOBsters. They actually score a higher percentage of baserunners than 23 of the 30 MLB teams. Or demands the Diamondbacks do a better job with a man on third and less than two outs, when only three teams bring those runners home at a higher rate than Arizona. I'm not sure if it's a result of baseball being a game where a 30% success rate at hitting is considered elite, and 70% of baserunners will be stranded. It goes against studies which have shown team victories tend to be better remembered.

Yet here we are, some recalling meltdowns that barely happened. Of course, some people simply have a narrative to push, e.g. "Torey sucks!" and will make up whatever history they want to support it.

"My job is to get us to the playoffs. What happens after that is f___ luck." — Billy Beane

The reason he said that is because baseball has the biggest element of random chance in any of the major sports. The difference in the spot where ball meets bat, between a game-ending fly-ball and a game-winning home-run, is so small as to be beyond the bounds of human skill. Sure, some are better at it than others. But even Mark McGwire hit a home-run fewer than every ten at-bats. A baseball game is a series of chaotic and inherently unpredictable events. Over a season of 162 games, less so. But the smaller you shrink that, the greater the odds of something unexpected.

If we presume a 26-game month, there's a better than even chance that a .500 team will lose at least four games in a row. It's about a one-in-three chance for a five-game losing streak, so having one is basically meaningless in terms of "proving" anything. The problem is that, when a season comes down to the last few games, you're basically in "playoffs before the playoffs". Take 2025, where the D-backs would have needed to win four of the last five games to make it in. At that point, to quote Beane, what happens is "f___ luck". It's really not up to Torey very much. And you can expand the principle backwards.

The Diamondbacks are, let's be honest, not going to compete for the division title any time soon. The Dodgers simply have too many competitive advantages. From having the reigning MVP on their books for $2 million this year, to that Godzilla-sized television contract, alone worth more than all of the D-backs' revenue streams combined. While the scales of balance have the Dodgers' thumb pressing down on one side, all we can hope for is to compete for a wild-card spot. And four years in a row, Torey Lovullo has got us there, successfully negotiating the shoals of injury and MarteGate to have the team playing meaningful baseball into late September.

Maybe it's just me, but realistically, it's hard to demand anything more.