Remember when Morrow tweeted this?:
I (and several others) went back and checked his Pitch f/x, and found that a significant fraction of his sliders have been moving almost like cutters for his last several starts. (This diagram outlines which pitch tends to have certain spin movements)
Upto his last 4 starts:
His last 4 starts:
In the first diagram, there's a visible blank spread between the FB (fastball) and the SL (slider), usually where the FC (cut fastball) tends to be. In the second diagram, that space has been taken over by a portion of the SL. Now, this seems like a case of Pitch f/x classifying his (supposedly) new cutter as sliders. That could definitely explain the fact that, over his last 4 starts, he threw 47.9% of his pitches as sliders.
I've outlined his "cutters" in purple:
Keep in mind that this is not perfect; I've only outlined the "cutters" that were in the blank spaces.