Welcome to the latest edition of RotoBallers Recently Promoted Prospects series for fantasy baseball! Here I discuss some recently promoted MLB prospects and rookies , making note of what I think their upside could be for fantasy baseball managers, and whether they are potential risers or fallers.We have seen 87 rookies make their MLB debut in 2021. This week, we got two big-time debuts out of the Seattle Mariners organization - outfielder Jarred Kelenic and starting pitcher Logan Gilbert. I ...