Complex sentence: Describing his grip of the cutter, he said, "it's really a four-seam fastball with pressure on the middle finger"; by adjusting the pressure that he applied to the ball with his fingertips, Rivera could vary the pitch's movement.
Split into simpler sentences: Describing his grip of the cutter, he said, "it's really a four-seam fastball with pressure on the middle finger". By adjusting the pressure that he applied to the ball with his fingertips, Rivera could vary the pitch's movement.