What is the largest (most massive) known body in the solar system that a professional pitcher could throw a baseball off of, i.e. that has an escape velocity lower than ~102 MPH? (45.33 m/s)
Assuming an object with the same density as earth (not very good approximation) then a spherical object with a radius of 2.5 km, would have an escape velocity of about 96 mph. A velocity reached by several MLB pitchers. There are probably several asteroids with a radius near this.
I don't think this is complete - there may be objects between Phobos and Vesta. Phobos and Vesta have too little mass to be rounded under their own gravity, so the escape velocity may depend on where you are standing.