As I sat with my boys watching the first inning of Game 5 of the recent ALDS game between the Houston Astros and the Tampa Bay Rays, I made a comment to them about how aggressive the Astros hitters were going after Rays pitcher Tyler Glasnow. It was as if they knew what was coming before the pitch was delivered.

One particular pitch that stood out was the second pitch of Jose Altuve’s at bat in that inning. After taking a curve ball, he jumped all over a high fast ball that came in at close to 100 mph on the radar. It was out of the strike zone, but the fact that Altuve seemed to be expecting a fastball made it look easy to hit.

So, what was going on during that first inning to make the Astros bats turn on so aggressively?

It turns out that Tyler Glasnow was unwittingly (at least you’d expect it was on accident) giving away which pitch he was throwing.

Apparently the Astros had watched some film, and someone picked up on a habit Glasnow has of coming set with his hands lower when he’s throwing a curveball, and raising his hands higher when he’s getting ready to throw a fastball.

The video below dissects the critical tip-off signal Glasnow was giving to the Astros.

You can see in the video that when Glasnow was intending to throw a fastball, his glove rest level was consistently just above his Rays logo. When he was

After Altuve bats, he appears to turn to his dugout and confirms that their suspicions were correct, that

The fact that the Astros were on to the tip-offs from Glasnow became even more obvious later, when Bregman scored. Just after he crosses the plate, he has a little chat with Carlos Correa. As you watch the video, you can see Bregman mouth to his teammate, “If it’s down, it’s a curveball. If it’s up, it’s a fastball.”

It appears as if there was some context behind what Bregman was telling Correa, and that Correa understood that what Bregman was referring to was the rest level of Glasnow’s glove when he came set.

You might think that something like this (picking up on minor cues) would be something that only happens in high school or lower level youth sports. However, this is one obvious situation where someone playing at the highest level of his sport overlooked (as did those who were on his side) the fact that he was giving away which pitch he was throwing throughout an entire inning, which ultimately factored in huge to the outcome of the game.