Installing a roller bearing or ball bearing would also require some sort of seal on both sides to prevent the bearing from being contaminated. That's more complex then it needs to be.
Frankly, I'd just run the roller with the supplied bearing for a while. Considering the low speed application and relatively few hours (unless the OP is a landscaper) it would be used, it would take years to wear out the factory supplied bushing.
He could spray the bushing with Fluid Film after each use.