"Before the postseason began, a number of clubs called the commissioner's office about sign stealing and the inappropriate use of video equipment," according to the statement. "The concerns expressed related to a number of clubs, not any one specific club. In response to these calls, the commissioner's office reinforced the existing rules with all playoff clubs and undertook proactive measures, including instituting a new prohibition on the use of certain in-stadium cameras, increasing the presence of operations and security personnel from Major League Baseball at all postseason games and instituting a program of monitoring club video rooms."
An Astros employee was seen sending frequent texts while possessing a small camera beside the Boston Red Sox dugout during Game 1 of the American League Championship Series. The man was removed from the media area, and an investigation ensued.
A similar complaint was levied against the Astros by the Cleveland Indians, their opponent in the American League Division Series.
"With respect to both incidents regarding a Houston Astros employee, security identified an issue, addressed it, and turned the matter over to the department of investigations," the statement continued. "A thorough investigation concluded that an Astros employee was monitoring the field to ensure that the opposing club was not violating any rules. All clubs remaining in the playoffs have been notified to refrain from these types of efforts and to direct complaints about any in-stadium rules violations to MLB staff for investigation and resolution. We consider the matter closed."
Astros general manager Jeff Luhnow told reporters that his team was "playing defense" by keeping an eye on their opponent, according to Pete Abraham of the Boston Globe. He added that they found the Red Sox weren't doing anything inappropriate.