A ball thrower accessory for use with a ball thrower is provided, the ballthrower accessory comprising aconcave, flexible cap including: an inner surface； an outer surface, at leasta portion of the outer surfaceretaining or including a plurality of structures extending outward therefrom；and a margin therebetween,the margin shaped to provide two proximal leaves defining a centralinvagination, two side leaves and adistal leaf. A combination of a ball thrower and the accessory is alsoprovided.
