Major League Baseball has meted out severe punishments for the Houston Astros after the team was caught stealing signs using cameras and video monitors at its home field, Minute Maid Park, and four members of the 2017 Astros no longer have jobs — Houston manager A.J. Hinch and general manager Jeff Luhnow, Red Sox manager Alex Cora and Mets manager Carlos Beltrán. Here’s everything you need to know about the unfolding scandal:

What is sign-stealing?

Sign-stealing is a long-standing baseball practice in which one team tries to decode the signs of its opponent. Those signs could be relayed from the catcher to the pitcher, or from the dugout to the catcher, or from one infielder to another, or from a base coach to a batter or runner. There is a constant exchange of signs by both the hitting team and fielding team during a baseball game. Figuring out what even one of them means — in the Astros’ case, the signs from catcher to pitcher, the most frequent target for sign-stealing — can give a team a major advantage, allowing batters to know, for example, if the next pitch will be a fastball or a breaking ball.

Is it illegal to steal signs in MLB?

Nope. It’s accepted tradition. Players and coaches try to steal their opponents’ signs, but they’ve traditionally done so mostly by watching the other team and trying to recognize patterns or sequences. Sign-stealing is as old as baseball itself. But stealing signs using camera, binoculars or other objects foreign to the game is illegal. Major League Baseball took steps to curtail sign-stealing in the digital age during the most recent offseason, according to multiple media reports. That followed a series of allegations of teams stealing signs using electronic means. In 2017, MLB Commissioner Rob Manfred had warned teams about electronic sign-stealing, while fining the Boston Red Sox for “sending electronic communications from their video replay room to an athletic trainer in the dugout.”

How did the Astros steal signs?

The Astros used a camera positioned in center field at Minute Maid Park to decode the signs from the catcher to the pitcher and inform the batter what kind of pitch was on the way. That camera was used by the team’s replay room, whose operators were supposed to help Manager A.J. Hinch decide whether to challenge an umpire’s call. But in addition to those duties, former bench coach Alex Cora (the now-former manager of the Boston Red Sox) instructed the replay room to relay the decoded information to a player, who would share it with teammates. That information was variously shared using the dugout phone, the cellphone of a staff member on the bench or another cellphone stored nearby.

Eventually, the Astros installed a video monitor displaying the same footage just outside the dugout so players could look at the video themselves. Players would bang on a trash can with a bat to signal to the hitter at the plate what pitch was coming. “Generally, one or two bangs corresponded to certain off-speed pitches,” according to Manfred’s investigative report, “while no bang corresponded to a fastball.”

When did the Astros start stealing signs?

The Astros started stealing signs using the replay room at the beginning of the 2017 season, the same season they defeated the Los Angeles Dodgers, four games to three, to win Houston’s first World Series. The team began using the monitor outside the dugout two months into the season.

The replay room scheme was revived during the 2018 season, but stopped sometime before the playoffs began. MLB’s investigation did not find any evidence that the sign-stealing racket continued into the 2019 season, when the Astros lost the World Series to the Washington Nationals, four games to three.

How did the Astros get caught?

A number of teams had suspicions about the Astros, but the sign-stealing only became public in November, when former Astros pitcher Mike Fiers told Ken Rosenthal and Evan Drellich of the Athletic about the scheme.

“That’s not playing the game the right way,” Fiers said. “They were advanced and willing to go above and beyond to win.”

But unnamed sources who spoke with the Athletic said Houston was far from the only club breaking MLB’s rules by using technology to steal signs.

“It’s an issue that permeates through the whole league,” one major league manager said. “The league has done a very poor job of policing or discouraging it.”

Who got fired from the Astros?

Let’s start with who got punished. MLB Commissioner Rob Manfred suspended Manager Hinch and General Manager Jeff Luhnow for the 2020 season. Manfred also banned Brandon Taubman, the team’s former assistant general manager, from working for MLB or any of its clubs for the 2020 season, after which he can apply for reinstatement, over a separate matter. Manfred also stripped the Astros of their first- and second-round selections in the 2020 and 2021 drafts, and fined the franchise $5 million.

Shortly after Hinch and Luhnow’s suspensions were announced, they were both fired by Astros owner Jim Crane.

What did Alex Cora do?

Cora was the manager of the Boston Red Sox in 2018 and 2019 before he and the Red Sox “mutually agreed to part ways” Tuesday night. But before that, he was the Astros’ bench coach in 2017 and the architect of the sign-stealing scheme, according to the commissioner’s report.

“Early in the [2017] season, Alex Cora, the Astros’ bench coach, began to call the replay review room on the replay phone to obtain the sign information,” the report says.

“Cora arranged for a video room technician to install a monitor displaying the center field camera feed immediately outside of the Astros’ dugout,” it says later.

Those are both clear violations of MLB’s rules on sign-stealing and in-game technology use. Cora, the report states, was the highest level Astros official with direct involvement in illegal sign-stealing, and, according to media reports, he brought a similar regime to Boston when he began serving as the team’s manager in 2018.

“Given the findings and the commissioner’s ruling, we collectively decided that it would not be possible for Alex to effectively lead the club going forward,” the Red Sox said in a statement Tuesday night.

But Manfred chose not to discipline Cora yet, because MLB is conducting a separate investigation into alleged illegal sign-stealing by the Red Sox in 2018, the year the team defeated the Dodgers in the World Series. Manfred said he was withholding punishment on Cora until that inquiry concludes.

Who else in baseball might be involved?

New York Mets Manager Carlos Beltran played for the Astros in 2017 and retired after the team won the World Series. He was hired as the Mets new manager in November.

On Thursday, Beltran stepped down as manager of the Mets.Beltran never managed a game for the Mets, lasting only two months in the role.

Beltran is the only named player in the commissioner’s report. It alleges that in the 2017 season, he and a group of unnamed Astros players “discussed that the team could improve on decoding opposing teams’ signs and communicating the signs to the batter.” That discussion was the impetus for the trash can-banging scheme.

Mets executives said in a statement Thursday that they met with Beltran on Wednesday night and Thursday morning and “agreed to mutually part ways.”

“Considering the circumstances, it became clear to all parties that it was not in anyone’s best interest for Carlos to move forward as manager of the New York Mets,” the team said.

In a separate statement, Beltran said, “I couldn’t let myself be a distraction for the team."

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