Sign Stealing in Baseball Dates Back to the 19th Century. Here’s Why the Houston Astros Sign Stealing Was Different.

A still from FRONTLINE's documentary "The Astros Edge.

A still from FRONTLINE's documentary "The Astros Edge. (FRONTLINE)

October 3, 2023

For the seventh year in a row, the Houston Astros are heading to the playoffs.

But hopes for another World Series win aren’t the only thing following the team into the postseason.

Some six years later, the Astros’ reputation continues to bear the stain from an illegal 2017 sign-stealing scheme that became one of the most explosive scandals in modern baseball history.

“It’s too big of a sin in baseball to be washed away ever,” says Tom Verducci, a writer for Sports Illustrated, in the new FRONTLINE documentary The Astros Edge: Triumph and Scandal in Major League Baseball, which premieres on the first day of baseball’s 2023 postseason. The documentary focuses on the Astros’ 2017 scandal, but as it also points out, illegally stealing signs is woven throughout baseball’s history.

Here, we take a brief look at that history, where the Astros’ sign-stealing scandal fits in and the new measures that were introduced to curb the practice.

A Brief History of Sign Stealing

During any baseball game, small physical gestures, or signs, are flying all over the place. They’re a way for players and coaches to communicate across the long stretch of the field.

Some of the most important signs are those between the catcher and the pitcher, strategically signaling which pitch to deliver. Catchers typically signal with a certain number of fingers between their legs to suggest one of three general kinds of pitches — fastballs, breaking balls and offspeed pitches. Pitchers will nod or shake their heads until the two players agree on what should be thrown.

“It’s two minds acting as one,” says Paul Dickson, author of The Hidden Language of Baseball: How Signs and Sign-Stealing Have Influenced the Course of Our National Pastime and other books on baseball. “So, the pitcher’s mind is also the catcher’s mind.”

Sometimes a batter can figure out what pitch they are about to receive through a pitcher’s inadvertent movements. Such signs are known as “tells.” For example, the legendary Babe Ruth curled his tongue before he threw a curveball.

Decoding both tells and intentional signs in baseball has always been legal and remains so to this day. “If you were in uniform and inside the parameters of the ballpark and you’re sitting in the dugout and you pick out a sign from there, that’s considered part of the game,” says Dickson. “[It’s] not cheating. It’s just that the other team is foolish enough to give a sign that was interpretable.”

Deciphering these signs can give major league batters a critical edge over the opposing pitchers, who are typically throwing pitches at speeds ranging from the low 70s to over 100 miles per hour. But using any form of technology other than one’s eyes to decipher and transmit information about signs in real time has always been considered cheating.

“When you cheat on the field, telling people when a fastball is coming, you’re really playing with the heart of the game,” Fay Vincent, MLB commissioner from 1989-1992, says in the documentary The Astros Edge.

Throughout baseball’s history, teams have been accused of or outed publicly for various schemes to “steal” signs, often involving people with binoculars or telescopes in centerfield relaying upcoming pitches through a buzzer system or a scoreboard operator.

The first reported case of sign stealing that was considered as crossing a line happened in 1876, almost 150 years ago. A team called the Hartford Dark Blues reportedly stationed a man inside a shack to alert batters to a curveball coming their way.

A famous moment in baseball history known as “The Shot Heard ‘Round the World” — when Bobby Thomson of the New York Giants hit a three-run home run off of Brooklyn Dodgers pitcher Ralph Branca to clinch the 1951 National League pennant — became tainted 50 years later. In 2001, Joshua Harris Prager reported in The Wall Street Journal that the New York Giants had been stealing signs at the time.

Prager’s reporting revealed that during home games a representative of the Giants would use a telescope to decipher signs of the opposing team from the owner’s box above centerfield. A buzzer system wired to the bullpen and the dugout was used to relay the signs. Players who received the information would then signal batters with subtle motions such as crossing a leg or throwing a ball in the air. Although it hasn’t been confirmed that the actual “Shot Heard ‘Round the World” was the result of a stolen sign, the controversy has tarnished Thomson’s game-winning home run.

The MLB Commissioner Steps In

In 1961, National League President Warren Giles issued a rule banning the use of a “mechanical device” to steal signs. But in the many years since, technology and analytics have dramatically reshaped the game — from live-replay that makes it possible to challenge an umpire’s calls to gathering granular data about players’ performance. As the technology has evolved, MLB regulations have held fast that technology is not allowed to give players an edge in real time.

“I think when you step over the line is when you start using the television cameras and the technology that they have now,” says Joe Nossek, who spent over four decades in baseball, first as a player and then as a coach, before retiring in 2004. He is known for his talents at decoding signs.

Before the Astros cheating scandal came to light, there were a number of other teams caught up in sign-stealing allegations. In 2017, the New York Yankees filed a complaint with the MLB commissioner’s office. They had footage of a Boston Red Sox staffer looking at his smartwatch and signaling to players. The Yankees alleged the Sox dugout was getting decoded sign information from the replay room and using it to relay the catcher’s sign when there was a runner on second base.

When asked about MLB’s investigation into the allegations, MLB Commissioner Rob Manfred said at a 2017 event that he believed he had authority to punish teams for this type of cheating, but added, “It’s just very hard to know what the actual impact on any particular game was of an alleged violation.

In a statement issued in September 2017 after MLB’s investigation, Manfred laid out the consequences: The Red Sox were found to have been using electronic equipment to steal signs and would face a fine. It was later revealed that during the course of the investigation, MLB learned that the Yankees had previously engaged in a similar scheme. Manfred also sent a memorandum on sign stealing to all baseball clubs in the league that this type of behavior would not be tolerated and put general managers and managers on notice that they would be held accountable in the future.

Little did the world know that at the same time that the Red Sox were penalized for stealing signs, the Houston Astros were also stealing signs in a similar way — and in another, more flagrant way, too. The scheme wouldn’t come to light until two years later when The Athletic reported on it.

Afterwards, the commissioner’s resulting report detailed two types of sign stealing. The first involved relaying decoded signs from the video replay room to the dugout using a runner, the dugout phone, a smartwatch or a cell phone, so that when there was a runner on second that runner could tip off the batter. At some point in the 2017 season, though, the Astros figured out a way to alert a batter during home games even when there was no runner on second: by banging a trash can near a monitor located “immediately outside the Astros’ dugout.”

The Houston Astros won the World Series for the first time in their club’s history that year and became the darlings of baseball. After the scheme was exposed, MLB fined the team $5 million, the league’s highest allowable fine, forced them to forfeit their first and second round draft picks for two years, and suspended general manager Jeff Luhnow and manager A.J. Hinch. When doling out these penalties, Manfred justified them by pointing to his September 2017 memo to clubs.

According to the commissioner’s report, the cheating was initiated and conducted almost exclusively by the players. But no players faced official punishment. Instead, they had been offered immunity for their testimony — a decision that Commissioner Manfred now says he regrets.

Enter PitchCom

Since the scandal, MLB has increased security in replay rooms and introduced a transmitter-receiver device called PitchCom that allows the catcher and pitcher to communicate without hand signals.

Beginning in the 2022 season, PitchCom was made available to all teams. Many adopted it quickly. Some showed distaste. Pitcher Max Scherzer, then of the New York Mets, believed that the device took away the legal ways players can decode signs, changing the way the game was played, and said the device should be “illegal.”

PitchCom continued to expand its offerings in the 2023 season by adding the capability for pitchers to transmit signs to the catcher, whereas earlier only catchers could transmit. This spring, Scherzer was seen using the device and, in a turnaround from last year, had positive feedback. But he said he still wants some rules governing PitchCom’s use.

Even with such innovations, Nossek believes that some people in baseball will always be looking for new ways to crack the codes in pursuit of victory.

“I think in the game of baseball, or probably most games, there’s always going to be teams that are going to try and find an edge to help them win games, ‘cause that’s what it’s all about in the end, is winning, right?”

Watch the full documentary The Astros Edge:

Kelsey Rightnowar

Kelsey Rightnowar, Murray Journalism Fellow, FRONTLINE/Missouri School of Journalism Fellowship

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