Mejia signed a minor-league deal with the Nationals on Friday that included an invite to spring training, Mark Zuckerman of MASNSports.com reports.
Mejia was assigned to minor camp Saturday, Ryan Divish of The Seattle Times reports.
Mejia has yet to report to Mariners camp as of Monday due to visa issues, Daniel Kramer of MLB.com reports.
Mejia signed a minor-league contract with the Mariners on Feb. 8.
Mejia signed a minor-league contract with the Royals on Monday, Lynn Worthy of The Kansas City Star reports.
Mejia was non-tendered by the Royals on Wednesday.
Mejia was optioned to the alternate training site Wednesday.
The Royals recalled Mejia from their alternate training site Wednesday.
Mejia was optioned to the Royals' alternate training site Thursday, Jeffrey Flanagan of MLB.com reports.
Mejia was added to the Royals' 30-man roster Thursday, Jeffrey Flanagan of MLB.com reports.