According to a Houston player, the Astros often knew what Darvish was about to throw by the way he brought the ball into his glove in the set position. (Darvish pitches exclusively out of the stretch.) The player said it worked like this: Darvish holds the ball at his side when he gets the sign from the catcher. Whether he re-grips or not as he brings the ball into his glove was the tip-off whether he was going to throw a slider/cutter or a fastball.