The Yankees are very paranoid about the Astros stealing signs.

In fact, according to the New York Post, an unidentified source familiar with the situation says the Yankees believed the Astros were using whistles to relay stolen signs to each other during Game 1 of the American League Championship Series.

“I don’t think it’s any secret they do it,’’ the person said. “They bang pipes. We have heard they have cameras around the park and that some way of communicating originates from their bullpen. Just look at their home record.’’

MLB on Thursday, ahead of Game 4 in the series that the Astros lead, 2-1, cleared Houston of any wrongdoing, The Athletic reported, citing unidentified sources.

"MLB investigated and found Astros did not engage in any activities prohibited by MLB policies. … MLB had an official in the camera well next to the #Astros’ dugout in G1 and one in the back of the dugout in G2. Neither officials nor umpires heard whistling," The Athletic's Ken Rosenthal tweeted.

As first reported by @martinonyc, the #Yankees suspected the #Astros used a whistling sound from their dugout in Game 1 of the ALCS as a way to convey signs to hitters. Per sources, MLB investigated and found Astros did not engage in any activities prohibited by MLB policies. — Ken Rosenthal (@Ken_Rosenthal) October 17, 2019

Teams are prohibited from signaling to hitters from the dugout through whistling or other means. MLB had an official in the camera well next to the #Astros’ dugout in G1 and one in the back of the dugout in G2. Neither officials nor umpires heard whistling. #Yankees won G1, 7-0. — Ken Rosenthal (@Ken_Rosenthal) October 17, 2019

Houston went 60-21 at home in 2019 and clearly the Yankees believe sign-stealing has something to do with it.

New York's Game 1 starter Masahiro Tanaka even said the team changed up signs to mess with the Astros in the first game. Apparently, it worked as Houston lost 7-0.

“We knew about it,’’ Tanaka said through an interpreter Sunday before Game 2. “They’re really good at picking things up. And on top of that, they play at a really high level.”

He continued: “We tried to make it more complicated. We definitely paid more attention to changing things up and tried to make it harder for them.”

The Astros have long been suspected of picking up tipped pitches and stealing signs — neither of which is illegal by the way unless electronics are used. Rays starter Tyler Glasnow said he was tipping signs in Game 5 of the ALDS when the Astros tagged him for four runs in the first inning.

Another former pitcher Seth McClung suggested Tampa Bay believed Houston was using a camera at Minute Maid Park to steal signs as well in that game as the Rays were using multiple signals even when the Astros didn't have runners on base.

Some believe this would be a reason why the Astros' home record was so much better than their road record (47-34) in 2019. Some believed they did the same thing in 2018. The only issue with that would be Houston was actually better on the road last season than they were at home posting an OPS+ of 116 on the road and 99 at home while scoring 51 more runs away from Minute Maid Park during the year.

All that pitch-tipping paranoia?

"I think it's kind of funny,'' Astros manager A.J. Hinch said (via ESPN.com).

The Yankees may be suspicious of the Astros stealing signs but a good reason New York lost Games 2 and 3 was because the Yankees scored a total of three runs in those games. New York knows it has to pick up its offense if it wants to win this series — sign-stealing or not.

"We just weren't able to get that big hit," Aaron Judge said after a Game 3 loss, via ESPN. "(I) had the situation (in the second inning with two out) where I had two guys on and wasn't able to come through. This is the postseason. You got to be able to come through in those situations."