They’re saying now that Luis Severino’s dismal start against the Red Sox in Game 3 of the ALCS—you know, the one that Boston ended up winning, 16-1—may have been compromised by tipped pitches.

According to Fancred’s John Heyman, various Yankees heard “chatter” about it from folks around the Red Sox. (Important to note that Heyman used the word “people,” not “players.”) The possibility was noted on the Red Sox broadcast by Lou Merloni, and Jackie Bradley Jr. was caught on camera, in the dugout, calling for a fastball moments before Severino delivered one.

The idea is that Severino did something in his pre-pitch setup, or even during the course of his delivery, that gave Red Sox hitters advance notice of what he was about to throw. We’ve covered the topic in this space before, regarding Johan Santana, Ben Sheets and Matt Moore, among other instances. The Baseball Codes itself has an entire section on pitch tipping, including the following passage:

Hall of Fame spitballer Burleigh Grimes was done in by his cap. Although he shielded the ball with his glove to keep hitters from knowing whether or not he was preparing for a spitter, members of the Phillies realized that the brim of his hat—visible above the top of his glove—would rise when he opened his mouth to spit, and laid off the ensuing pitches. It worked beautifully, at least until the pitcher wised up and got a bigger cap.

Picking up tells can be a veritable art form, with master practitioners noticing things about a player that escape even their most astute. Bob Turley, for example, in addition to being a great sign thief, could also pick up tells better than almost anybody in the game.

“When (Connie Johnson) starts his windup, he’ll move his foot to the other end of the rubber if he’s going to throw his screwball,” he once told Mickey Mantle, as reported in Baseball Digest. “Billy Pierce always wore a long, heavy sweatshirt, no matter how hot it was. When he went into his glove to grip a fastball, you would see the back of his wrist. When he was going to throw a curve, he would get deeper in there and you would not see his wrist. Early Wynn, when he pitched from the stretch, where were his hands before he threw? If he was going to throw a knuckleball, they were at his belt. For a fastball, he’d come up under his chin. Slider, around his nose. Curve, up at his forehead. Jim Bunning altered his windup a little depending on what he was going to throw.”

If this is true it gave the Red Sox a huge advantage, allowing them to lay off as Severino’s devastating slider sailed outside the strike zone. On one hand, this is supported by fact: According to CBS Sports, Boston hitters offered at only six of the pitcher’s 15 sliders on the day, a 40-percent rate that’s lower than the 47.2-percent rate he posted during the regular season. On the other hand, if one Red Sox hitter had swung just once more at one of those pitches, the offer rate against him would have been effectively the same as it had all season.

Still, Severino virtually abandoned the pitch toward the end of his outing, throwing only two sliders across the final nine hitters he faced. That left him with only a fastball and a changeup, and as we’ve long since learned, fastball pitchers—no matter how potent the fastball—have a difficult time surviving in the big leagues without a potent breaking pitch to accompany it.

Whether the right-hander was actually tipping is up for debate. Severino’s splendid first half—a 2.10 ERA with 132 strikeouts against only 26 walks, and six homers allowed with a 15-2 record over 17 starts in the season’s first three months—contrasts starkly with his final three months: 5.20 ERA, 88 whiffs and 20 walks, 13 homers over 15 starts, a 9-6 record. But here’s the thing: Hitters were waving at his slider at almost exactly the same rate all season. By this metric, anyway, Severino’s late-season failures had nothing to do with him fooling them less. The fact that he lost nearly a mile-per-hour off his fastball between his June peak and October might have more to do with it, or that his slider’s movement across the strike zone steadily decreased as the season wore on.

The Yankees, of course, aren’t talking, and neither are the Red Sox. Trade secrets like this are valuable commodities, after all. One thing to be certain of, however, is that if Severino was tipping, the Yankees will be all over it this off-season, and come spring training the righty will have something to work on in addition to his regular regimen.