Gray’s slider
Gray’s slider has a lot of downward break on it (also acknowledging the deceptive camera angle here). It looks like it breaks sharply and right-handed hitters especially have trouble picking it up. He gets some truly awkward swings and makes guys look pretty bad when he has them set up for his slider.
Gray’s fastball-slider combo
Not surprisingly, he gets some uncomfortable swings at his slider and some late swings on his fastball when he uses one to set up the other, especially when he uses his slider to set up his fastball as he does on the strikeout found above. As for the GIF below…just watch the helpless swing on the slider for strike two and try not to get giddy.