This period of American League history might be defined this way:

The Astros landed Justin Verlander in August 2017 and won the ALCS because they had him and the Yankees did not. Houston went on to win its first championship.

The Astros landed Gerrit Cole after the 2017 season and the Yankees did not, and reached the 2018 ALCS that the Yankees did not, in part, because they did not have Cole to face the eventual champion Red Sox in the division series.

The Astros landed three pitchers on deadline day 2019, notably Zack Greinke, and the Yankees obtained an A-ball pitcher named Alfredo Garcia. The Astros did not claim the AL title on July 31. But the Yankees and Astros have been the AL’s dominant teams this year and — at minimum — on paper Houston moved ahead at the deadline.

“Let’s find out,” Brian Cashman said Wednesday.

I am always cautious when narrative flows one way strongly. We have seen lots of incidents of teams being named the winner of the offseason or the trade deadline and reality not honoring the preconceived script. I remember in 2007, for example, telling Yankees officials they blew it by getting outbid by the Red Sox for Eric Gagne. Boston went on to win the World Series, but a terrible Gagne was about the biggest impediment to that.

Last season, the Dodgers won the deadline with Manny Machado and the Red Sox won the World Series with Nathan Eovaldi and Steve Pearce.

So we will see how this will play out. Maybe the Yanks will acquire Luis Severino, Dellin Betances and Jonathan Loaisiga from the injured list and Deivi Garcia from the minors and that will fortify the pitching staff in a way Cashman and his crew could not at the deadline. But the Yankees knew the problem.

They worked diligently to try to upgrade the pitching. They didn’t. Period.

The 2015 Yankees had a six-game AL East lead at the deadline, added just spare bat Dustin Ackley and watched the restocked Blue Jays soar by them to win the division. Will this Yankees team also blow a big lead? Probably not. But as in 2015 there is a sense they are running on fumes physically and emotionally after enduring so many injuries this year and seeing the rotation buckle over the past two weeks. The roster and spirits would have been lifted with an addition that did not come.

Why didn’t it?

Well, two fourth-place NL teams in the Mets (Marcus Stroman) and Reds (Trevor Bauer) beat all the main contenders to two big starters. That the Mets’ Noah Syndergaard and Zack Wheeler, the Giants’ Madison Bumgarner, the Rangers’ Mike Minor and the Diamondbacks’ Robbie Ray stayed put suggested more than the Yankees did not accept the asking prices. Like Bumgarner and Minor, Greinke had a no-trade clause that included the Yankees and there was no way Greinke was saying “yes” to New York.

“I feel comfortable walking away with everything that was in front of me,” Cashman said. “Those weren’t real opportunities with everything that was in front of me.”

In the end, though, the Astros again found a way to upgrade their arm stockpile while having a similar downturn to the Yankees in their farm system due to previous trades, graduations to their major league roster and downturn in performance/injury. Greinke joins Verlander and Cole atop the rotation.

Aaron Sanchez, obtained from Toronto, works at the bottom with lefty Wade Miley, a one-year $4.5 million offseason signing who has greatly outperformed Yankee southpaw moves from the offseason: J.A. Happ, James Paxton and CC Sabathia.

Sanchez is the kind of big arm/stuff guy who Houston has had success refining. He is an injury risk. He is 3-14 with a 6.07 ERA. But in his last three starts against potential AL playoff teams Boston, Tampa Bay and Cleveland, Sanchez has walked one and struck out 20 in 15²/₃ innings, suggesting he might be at least an overpowering pen arm come October.

In another trade with Toronto, Houston also added reliever Joe Biagini, who has held righties to a .668 OPS this year with one homer in 126 plate appearances. (You know which team has a predominantly righty lineup? The Yankees.)

Keep in mind there also are not August waiver trades this year (that is how Houston pilfered Verlander in 2017). So July 31 was the last time to do make a deal. And somehow the deadline came and went with Stroman playing for a New York team, just not Yankees; Clint Frazier nearing his 25th birthday and 200th Triple-A game still property of the Yankees; and the Astros having again navigated to rotation upgrades that eluded the Yankees.

You can’t win the AL pennant on July 31. But can you lose it?