After the non-waiver trade deadline passes, teams can still make trades. Before teams can deal players, they must offer them on waivers to every other team in baseball. If they choose to use revocable waivers, the offering team can pull back the player if another team claims him, or choose to work out a trade. If the players clears waivers, then the club can trade him to any team in baseball.
It’s not surprising that Joakim Soria went unclaimed by any team in major-league baseball. The Kansas City Royals signed Soria to a three year, $25 million deal last winter.