Thanks to mlbtraderumors for this
Any player can be put on waivers by his team, and the player does not need to be informed.
Other teams have the chance to make a claim on the player during a 47 hour window.
If the player is claimed, the team that placed him on waivers has the option of pulling him back. If the team pulls him back they can’t trade him for 30 days.
If his team decides not to pull him back:
Option 1: His team can work out a trade with the team that claimed him. Any player involved in the trade who is on a 40 man roster must go through waivers first.
Option 2: His team can just dump him and his salary on the team that claimed him, getting no player in return.
Option 3: No one claims him, and his team is free to trade him to any team.
If more than one team places a claim on a player, the winning claim is awarded based on worst record or the league the claiming team is in.