Waivers must be secured before certain types of transactions can be completed.
There are two types of waivers (release waivers and assignment waivers), and while there is only one type of release waiver (Outright Release), there are three different types of assignment waivers (Trade Assignment, Optional Assignment, and Outright Assignment). Each type of waivers has a special set of rules that apply.
The MLB waiver list is transmitted at 2 PM (Eastern) every business day. Every day is an MLB business day during Spring Training and the MLB Regular Season, but because Saturday and Sunday are not considered MLB business days during the off-season, the MLB waiver list is transmitted at 2 PM (Eastern) Monday through Friday (only) during the off-season.
If a club requests a waiver prior to the 2 PM (Eastern) deadline, the waiver request is transmitted that day. If the waiver is requested after 2 PM, the waiver request will not be transmitted until the next business day. A player remains on waivers for two business days, during which time any of the other 29 MLB clubs can make a claim. At 1 PM on the second business day after the waivers are requested the MLB office determines if any claims were made, and if so, which club is awarded the claim.
A club can place no more than seven players on assignment waivers (Trade, Optional, and/or Outright) per day, and a club can make a maximum of 50 assignment waiver claims per week.
A player on a Disabled List cannot be placed on Trade Assignment Waivers or Optional Assignment Waivers until he is eligible to be reinstated from the DL.
A player on a Disabled List cannot be placed on Outright Assignment Waivers until he is both eligible to be reinstated from the DL and healthy enough to play.
Neither assignment waivers nor release waivers can be requested on a player while he is on the Bereavement List, Military List, Suspended List, Disqualified List, or Ineligible List.
Outright Release Waivers (but NOT assignment waivers) may be requested on a player while he is on the Voluntary Retired List.