The Washington Nationals were given a heads up to the Houston Astros cheating ways once it became guaranteed the two teams would match up in the 2019 World Series.

While the sign-stealing scandal was revealed long after the postseason, a third of the teams around the major leagues were already skeptical or had caught on to how the Astros handled business.

“It was a big open secret, really big,” said a veteran scout from another team whose coverage included the Astros, according to Barry Svrluga and Dave Sheinin of The Washingon Post. “Throughout baseball, throughout the scouting community, for several years, not just starting in 2017. I would say probably 2016, maybe earlier, through [2019], things were going on that were blatantly against the rules.”

Many thought the World Series would be the stage where the Nationals, the NL's Cinderella story, would fall flat to a team with championship pedigree, yet many teams were hoping the Astros got what they had coming for a while — a loss at the biggest stage.

“The whole industry knows they’ve been cheating their a**es off for three or four years,” said an executive from a team that faced the Astros in the playoffs during that span. “Everybody knew it.”

That same executive estimated 10-12 teams had complained to Major League Baseball about the Astros over the years. Another executive from another team interviewed by The Washington Post agreed with that number.

“They seemed to be all over certain pitches from our guys and laying off others,” a major league GM of a team recalled of the Astros’ ­hitters back in 2017.

RECOMMENDED (Article Continues Below)

Soon enough, the Astros' hitters suddenly didn't just get a finger advantage, but they would obliterate opposing pitchers with monk-like discipline and ruthless power at the plate.

The banging on cans, the camera in center field and the monitor near the dugout were dead giveaways that something wasn't common in that clubhouse, and many teams had caught on to the Astros' fishy strategies.

Word didn't take long to reach the Nats, who managed to switch up their signs in time to keep the Astros on their toes during a long seven-game series that eventually crowned them champions — despite playing in an uneven playing field.