The most basic signs in baseball are the signs between the catcher and the pitcher. The catcher displays a signal, usually just by holding up one, two, or three fingers, and agrees with the pitcher about what kind of pitch the pitcher is going to throw. The main goal of varying the pitches is to keep the batter guessing, as a batter is far more likely to hit a pitch if he can predict the speed, release point, trajectory, and type of spin on the ball. For example, the fastest pitches are “fastballs”, which come across the plate at roughly 160 km/hour. There are more deceptive pitches, like the “changeup”, which are usually thrown to look like exactly like a fastball but come across the plate about 20 km/hour slower than a fastball. This speed discrepancy confuses the batter’s timing and makes it difficult to hit. I won’t delve into too many intricacies about pitching, but suffice it to say that when a batter knows what kind of pitch is coming at him, he is far, far likelier to hit the ball. These mind games are by far the most interesting part of the sport.
Pitchers and catchers have always needed to develop a system to confuse any runners, who can sometimes see the catcher’s signals. If the signalling system is obvious, runners can signal to batters about upcoming pitches, and therefore give the batter a huge advantage. This “sign-stealing” has long been accepted as part of the game if done organically; it is against the rules when technology comes into the picture. If you are playing poker with someone who does not do a good job of hiding their cards, you are not going to be penalised for looking. But you will be penalised if you install a secret camera to see your opponent’s cards. The Astros did just that.
The Astros had a camera installed in their stadium that was aimed directly at the catcher and fed directly to a monitor near the team’s “dugout” (where the team stays when they are not batting or on the field playing defence). Players could easily access this monitor in a large hallway, where non-player employees sat, watching the signals. After watching a few batters’ worth of pitches, they could then decipher the pitcher/catcher signalling system and give this information to a batter on second base. The only question was how they would communicate this information about the upcoming pitch to the batter. The players initially experimented with clapping, whistling, and yelling, but determined banging a trash can with a bat was most effective because it could reliably break through crowd noise. One or two bangs corresponded to a breaking ball (a pitch with a sideways or downward motion), and no banging indicated a fastball. This rudimentary setup was quite effective: Astros batters had a huge advantage during every home game, and it showed in their championship-winning season.
In the days following the bombshell article, Major League Baseball launched an investigation into the Astros and their sign-stealing. In the meantime, baseball fanatics — from regular fans to Youtubers to sportswriters — spent the next weeks poring over YouTube videos of Astros home games. These internet sleuths posted the results and data on various sites, such as this post on Reddit:
“I’m an Astros fan. They cheated during the 2017 regular season — the evidence is clear. In an attempt to understand the scope of the cheating and the players involved, I decided to listen to every pitch from the Astros’ 2017 home games and log any banging noise I could detect. These are the results of my efforts. I’ve logged over 8,200 pitches and found banging before over 1,100 of those pitches.”
Fans watched untold hours of footage, produced quality data, and ran statistical analyses about how likely it was that this cheating affected the outcomes of many games. Even before the League announced the results of its investigation, it was objectively clear that the Astros were cheating, and that this cheating altered the outcomes of many games during their 2017 World Series run. Thus, when the League announced the results of their investigation on January 13, 2020, people expected historic punishments.