Mike Fiers didn't blow the lid on the Houston Astros' sign-stealing operation until early this year.
But the Boston Red Sox knew what the Astros were up to entering the 2018 American League Championship Series -- thanks to a tip from Fiers.
That's according to Red Sox designated hitter J.D. Martinez, who revealed Thursday that Fiers made him aware of the Astros' illegal sign-stealing system before the 2018 playoffs.
"The only way I ever found out was towards in the playoffs when Fiers -- who is a very good friend of mine -- he reached out to me and said, ‘Hey, make sure you're doing this because this is what these guys are doing in the playoffs,' " Martinez told WEEI's "Ordway, Merloni & Fauria" radio show. "I was like, ‘What?! How is this a thing?' "
Martinez said he mentioned Fiers' tip to Red Sox manager Alex Cora, who told Martinez "about the whole system," having served as Houston's bench coach in 2017.
In-depth news coverage of the Greater Boston Area.
"That was why it was so crazy," Martinez said. "[Cora] was so relaxed going into those playoff games because he knew -- we were ready for it."
New Red Sox catcher Jonathan Lucroy suggested Thursday that many MLB teams were aware the Astros were cheating.
But Cora had specific knowledge of Houston's operation, and considering Boston dispatched the Astros in five games in the 2018 ALCS en route to a World Series title, it's worth wondering how much Fiers' counter-intelligence benefited the Red Sox (if it all) in their series victory.
It's also worth wondering if Cora shared Houston's method of stealing signs -- which involved a TV monitor next to the dugout and banging on trash cans to alert hitters of certain pitches -- with the 2018 Red Sox, who are under investigation for their own sign-stealing operation.
Martinez insisted Boston didn't adopt any part of the Astros' system, however.
"You can put me on any lie detector," Martinez said. "Alex Cora never influenced us and never told us about that thing."