MLB 2011 season

Any player under contract may be placed on waivers ("waived") at any time. After MLB's July 31 trade deadline and through to the end of the season, however, a team must place a player on waivers if that player is to be eligible to be traded.

If a player is waived, any team may claim him. If more than one team claims the player from waivers, the team with the weakest record in the player's league gets preference. If no team in the player's league claims him, the claiming team with the weakest record in the other league gets preference. In the first month of the season, preference is determined using the previous year's standings.

If a team claims a player off waivers and has a viable claim as described above, his current team (the "waiving team") may choose one of the following options:

• arrange a trade with the claiming team for that player within two business days of the claim; or
• rescind the request and keep the player on its major league roster, effectively canceling the waiver; or
• do nothing and allow the claiming team to assume the player's existing contract, pay the waiving team a waiver fee, and place the player on its active major league roster.

If a player is claimed and the waiving team exercises its rescission option, the waiving team may not use the option again for that player in that season. If no team claims a player off waivers after three business days, the player has cleared waivers and may be assigned to a minor league team, traded (to any team), or released outright.

The waiver "wire" is a secret within the personnel of the Major League Baseball clubs; no announcement of a waiver is made until a transaction actually occurs. Many players are often quietly waived during the August "waiver-required" trading period to gauge trade interest in a particular player. Usually, when the player is claimed, the waiving team will rescind the waiver to avoid losing the player unless a trade can be worked out with the claiming team.