Dayton Moore seems to think that anything worth doing is worth doing twice (or more). Witness last offseason when he signed Brian Anderson. Then he signed Scott Podsednik. Then for good measure, he brought in Rick Ankiel.
The two were designated for assignment after hot stove activity added Melky Cabrera and Nathan Adcock to the roster (Jeff Francoeur‘s signing landed Philip Humber on waivers, where he was picked up by the Athletics). Following the Zack Greinke trade that added Alcides Escobar, Lorenzo Cain and Jeremy Jeffress to the 40 man roster, Arias and Zawadzki were the selections to go. They both cleared waivers and have been assigned to Omaha. Should an injury befall a Royals infielder, Arias should be the first option to come up, with Zawadzki somewhere after him.