Maybe. Or maybe it's easy to crush a grooved fastball when it's an average pitch and the rest of the arsenal isn't good or getting thrown for strikes.
When you throw 98 with sick movement like Sanchez, no one sits on the curve, so sometimes s*** like that will happen. It's especially true with a geezer like Ortiz, who has to cheat to get around on a fastball that good.
In Hutch's case, the fastball is 91-94 with little movement, and there's no plus breaking ball to worry about, so hitters sit dead red on him. At least that was the case this year. If Hutch's slider magically re-emerges, I think we'll suddenly find that his fastball is also much more effective.