Swarzak cleared waivers and elected free agency Wednesday.
The Royals designated Swarzak for assignment Saturday, Alec Lewis of The Athletic reports.
Swarzak's contract was selected by the Royals on Friday.
Swarzak signed a minor-league contract with the Royals on May 14.
The Diamondbacks released Swarzak on Friday.
The Diamondbacks designated Swarzak for assignment Sunday.
Swarzak had his contract selected by the Diamondbacks on Wednesday and was recalled from the alternate training site.
Swarzak was reassigned to Arizona's minor-league camp Sunday.
Swarzak signed with Arizona as a non-roster invitee Thursday, Zach Buchanan of The Athletic reports.
Swarzak was released by the Phillies on Monday, Matt Breen of The Philadelphia Inquirer reports.