Orrrr. I could come slow pitch them some baseballs. They aren't that hard to hit. You just need a little practice.
Also, I think an actual eephus pitcher would be problematic. (Position players can't be challenged) The strike zone is supposed to be 3 dimensional but we decided to just say screw it, that's too hard for non-humans to deal with, so it's now a plane at an arbitrary point on the plate. You no longer have to "cover the plate" as intended.
This has decreased the value of off speed pitches and by effect, increased the value of relatively straight Velo. Backdoors miss the simplified for computer/camera computer strike zone by passing over the imaginary rectangle but still hitting the real strike zone. Front doors or clipping the front of the the true strike zone is the same thing.
An eephus reliever could be incredibly successful in today's baseball (with some real stuff mixed in), but the simplified strike zone for the stupid computers sort of messes that up.