The New York Yankees believe the Houston Astros were whistling to steal signs during Game 1 of the ALCS, and they're not happy about it.

"The whole dugout was pissed," a source told Andy Martino of SNY. "Everyone was chirping."

A Yankees coach reportedly noticed the whistling coming from the Astros dugout during certain pitches last Saturday. The two sides argued about the situation during the game, which apparently caused Houston to stop the whistling in Game 2.