I find it absolutely amazing that, instead of admitting you're wrong when confronted with the pitcher's own words
about what he's throwing, you'd continue to "figure it out."
If Cingrani said it was a slider, then he threw a slider.
BTW, your definition of slider is wrong.
In baseball, a slider... is a pitch that breaks laterally and down, with a speed between that of a curveball and that of a fastball.
The break on the pitch is shorter than that of a curveball. The release technique of a slider is between a curveball and a fastball. The slider is similar to the cutter, a pitch which is thrown as a fastball, but differs in the sense that a slider tends to be more of a breaking ball.