Gosh, Coach Paul, didn't anyone ever tell you about the crossfire?
When my wise and wonderful pitching coach was showing me how to short-arm my delivery (which gave me two ways to throw sidearm) he said, "And this is where you use the crossfire...And always with the slider." He was telling me that my best pitch, that 86MPH hard slider, would be even more effective with that addition. You can be sure I picked up on that beautiful and lethal move, and I ended up using it with every pitch I threw, which further discombooberated, confused and infuriated the batters who struck out all the time! If you had learned to use that move, you would not have to worry about your slider; it would work very nicely for you.
And I never tire of telling this story about Allie Reynolds, just to illustrate a point: if you need a batting-practice pitcher, get a batting-practice pitcher and NOT a fireballer who can hit 100 MPH---or faster. The story is that Mr. Reynolds was at Oklahoma State, and because of his powerful arm he did very nicely in various sports, so the baseball coach asked him to throw some BP to the hitters. He said okay, and he got up on the mound---but what he threw to the hitters was NOT batting practice. He fired that high cheese in there, 95-100 MPH, and he struck out one batter after another. The coach looked at him for a minute and then hollered, "Go get a uniform! You're on the team!" 8)