Commissioner Rob Manfred confirmed MLB will investigate the Red Sox "with the same thoroughness and vigor" as the league looked into allegations against the Astros.

Major League Baseball has launched an investigation into possible illegal sign-stealing by the Boston Red Sox in 2018 that commissioner Rob Manfred promised will follow the template of the one into allegations against the Houston Astros in 2017 and 2018. Manfred characterized the Houston investigation last month as “probably the most thorough investigation that the commissioner’s office has ever undertaken.”

“We’re going to investigate the Red Sox allegations with the same thoroughness and vigor that we did Houston,” Manfred told SI Tuesday.

Like Houston, Boston faces severe discipline because the activities in question occurred after two warnings by MLB that defined the illegal use of technology: one in September 2017 and another, more tightly-worded regulation in March 2018.

Manfred telephoned Red Sox principal owner John Henry on Monday night to inform him of the investigation. “I’ve got no choice here,” the commissioner told Henry.

In the Houston investigation, which has taken three months, Major League Baseball interviewed more than 60 people and acquired more than 70,000 e-mails in addition to text messages obtained when club employees were required to turn over their phones. Henry asked Manfred if Red Sox personnel would be subject to the same type of disclosure. Manfred assured him that the same procedures will be used.

Major League Baseball learned of the possible Boston infraction during its investigation of the Astros. MLB planned to pursue those allegations privately but made public those efforts only after The Athletic reported the Red Sox violated MLB policy by using their replay monitor to decipher sign sequencing of opponents.

MLB is expected to announce penalties in the Houston investigation within the next two weeks. At the heart of the investigation are two allegations that occurred after Manfred put teams on notice in 2017 about the misuse of technology, which was prompted by his fining the Red Sox for using an Apple Watch to relay signs from a clubhouse monitor to the dugout.

The first allegation regarding the Astros was a scheme that according to sources lasted almost three months in the 2017 regular season in which the Astros stole opposing catchers’ signs from a monitor behind their home dugout that was connected to a centerfield camera. Astros personnel would alert the hitter when an off-speed pitch was coming by banging on a trash can.

MLB also investigated reports that in 2018 front office personnel ordered the surveillance of opposing dugouts with cameras.

In addition to severe fines, the Astros almost certainly face the forfeiture of multiple high draft picks because Manfred’s September 2017 memo specifically warned “future violations of this type will be subject to more serious sanctions, including the possible loss of draft picks.” Access to talent is considered a more pernicious penalty than fines.

Manfred is not expected to act against individual players, especially given the difficulty of proving who designed or benefited from such a system. Management personnel, including manager A.J. Hinch and general manager Jeff Luhnow, have more exposure. MLB holds them to a higher standard because of their leadership positions, even if only as overseers, if not participants.

During the 2017-18 offseason, Manfred and his office learned that sign stealing via electronic means had become common around the game, an unintended consequence of moving real-time replay monitors near dugouts for the sake of expediency.

On March 27, 2018, the commissioner’s office, under the signature of chief baseball operations officer Joe Torre, sent a three-page memo to all club presidents, general managers and assistant general managers defining the limits of technology. Manfred’s intention was to remove whatever lack of clarity may have existed from his 2017 warning.

The second page of the memo plainly states, “Electronic equipment, including game feeds in the Club replay room and/or video room, may never be used during a game for the purpose of stealing the opposing team’s signs.”

In the same paragraph, the memo doubles down on the regulation by stating, this time in boldface type, “To be clear, the use of any equipment in the clubhouse or in the club’s replay or video rooms to decode opposing club’s signs during the game violates this regulation.”

MLB is investigating whether the Red Sox violated that regulation in the regular season by players using the replay monitor to learn the sequence of signs used by opposing teams. Knowledge of those signs could be used when a runner reached second base, whence he could alert the hitter of the type of pitch.

In 2018 Boston posted an OPS with runners in scoring position of .872, the highest in the majors and the highest in the previous 12 years. (Seventy-seven percent of those plate appearances occurred with a runner at second.)

Such violations would have been far more difficult in the postseason because MLB stationed security agents around replay monitors, a practice that continued in the 2019 regular season.

According to sources, Manfred is considering two different avenues to further guard against the illegal use of technology: additional technology that would involve electronic means of transmitting the catcher’s signs to the pitcher, or the elimination of all technology except the replay monitor. Video rooms, for instance, would be shut down once the first pitch is thrown.