Generally, "earning it" entails statistical production...
Frelick in 158 MILB games: .332/.407/.479/.886
Mitchell in 132 MILB games: .273/.382/.419/.801
Wiemer in 236 MILB games: .274/.367/.506/.873
Also, I don't know where you're getting it from that Wiemer is a faster runner. They both grade out as 60/70 runners.