If he can't throw 100 anymore, does he need to develop a third pitch to remain dominant? Obviously he doesn't have to worry about anyone seeing him more than once, but that still gives hitters a 50/50 shot to guess what pitch is coming and sit on it (which is why it's critical to mix it up as noted above). Kinda like Devin, if you have an average fastball and a good breaking pitch, you better be really on your game or it's going to be a struggle. Or imagine Patrick with just 2 pitches.