The Yankees were always a delicate concept this season. They have a 26-man roster by rule. But most days too many spots were filled by the geriatric or journeymen used to making every spring-training road trip.

What steeled them for success despite the shortcomings was a formula of Gerrit Cole (still owner of the largest pitching contract ever given) plus Aaron Judge (largest per-annum position player ever) plus a deep bullpen.

But what happens when the Jenga pieces begin to be removed from such a flimsy structure? Judge was taken out of the lineup beginning June 4 and took the offense with him. The Yankees mainly survived over the next month because when they had a winnable game, their deep relief corps sealed a victory.

However, through overuse and/or regression to the mean — it turns out that Ian Hamilton, Tommy Kahnle and Nick Ramirez aren’t actually the three greatest relievers ever — the pen has gone from the majors’ best to a nine-game period as arguably the worst. The Yanks are 2-7 in that time.

Is that a blip?

Because if it isn’t, how do the Yanks even stay in playoff contention between now and whatever date-to-be-named-later that Judge returns?

For the dirty little secret is that, with all the hand-wringing about the Mets overexposing their thin bullpen with short starts, the Yankees through Monday had just one more start of at least six innings (34 to 33). And the Mets actually had more five-inning starts (68 to 66). Fifteen of the Yankees’ 34 six-inning starts were by Cole.

But as was exemplified Sunday when Cole was dominant over six innings (11 strikeouts, one run, two hits) even the ace needs help. First, he had no margin for error while he was in the game because the Judge-less offense could not do enough damage against Colorado’s putrid starter Chase Anderson. Then the bullpen collapsed and for the first time in franchise history the Yankees lost via blowing two multi-run leads from the eighth inning onward.

This is a big U-turn because the pen actually had been an organizational success story. It wasn’t like paying Cole and Judge at the top of the market. In fact, the Yanks had gotten away from the model in which they had among the highest-paid relievers ever with Zack Britton and Aroldis Chapman. They also were facing a season without Scott Effross and Lou Trivino, who both underwent Tommy John surgery. And they lost Jonathan Loaisiga early in the schedule.

But the Yanks were like a factory. They could have Hamilton and Ramirez on non-roster contracts and use their pitching lab to evoke excellence. That duo was part of a deep pen that through July led the majors in bullpen ERA (2.79), batting average against (.213), fewest homers allowed (24) and lowest slugging percentage (.331) while toting a 9.4 percent walk rate and 24.2 strikeout rate.

Central to the success was the ability to take the air out of the ball. For a long period around relievers such as Chapman, Dellin Betances, Andrew Miller and David Robertson, the Yanks had among the best power pens ever. But through July 4, the Yankee pen was thriving by removing exit velocity and keeping the ball out of the air. Their 52.2 percent ground-ball percentage from the pen was the third best since Fangraphs began tracking the stat in 2002.

But in the nine games after July 4, the ground-ball rate was 41.8 percent and the before-and-after horror followed: the second-worst ERA (7.91), homers allowed (eight) and slugging percentage (.556) plus a 12.9 walk rate and 16.6 whiff rate.

Again maybe it is just a bad blip for a strong group … or is it midnight for the Hamiltons and Ramirezes and Kahnles? Perhaps most troubling is that Michael King’s struggles are not contained to this period. He has been bad for almost six weeks. Before that, he was the third-most valuable player on the team.

Aaron Boone was using King as a hybrid, multi-inning force to help camouflage the short starts. The first nine times the righty was used for at least two innings, he did not give up a run (covering 19 ¹/₃ innings) and the Yankees were 9-0. But he has given up runs three of the four times since in his at-least-two-inning stints and the Yanks lost all three. Boone clearly was hoping to get two innings out of him Monday night when King came on in the seventh with the Yankees ahead 3-1.

The dramatic moment was the tying two-run homer King yielded to Shohei Ohtani. But what was unforgivable was walking Eduardo Escobar after getting ahead 0-2 to allow Ohtani to bat in the seventh. King walked three in all, a wildness that meant there would not be two innings. He suffered his fourth blown save since June 8.

The pen failures exacerbate a lineup that generally cannot absolve the failures. For the 19th time in 35 games since Judge injured his right big toe, the Yankees did not exceed three runs. They lost 4-3 in 10 innings to the Angels and a team with too many holes and key Jenga pieces pulled out fell alone into last place.