The three MLB waiver periods are:

1. September 1st through the 30th day of the MLB regular season;

2. 31st day of the MLB regular season up until one hour after the MLB Trade Deadline;

3. One hour after the MLB Trade Deadline through August 31st. 

WAIVER CLAIM PRIORITY

If a player is claimed by only one club, that club is awarded the claim. If more than one club makes a claim, the club with the lowest winning percentage (regardless of league) either from the previous season (beginning on the day after the conclusion of the MLB regular season through the 30th day of the MLB regular season) or on the day the player clears waivers (beginning on the 31st day of the MLB regular season through the last day of the MLB regular season) is awarded the claim. If two clubs with the same winning percentage make a claim, the club in the player's own league is awarded the claim. If two clubs from the same league make a claim and they are tied in the standings, the club with the lowest winning percentage from the previous season is awarded the claim. If the clubs are still tied, standings from two years back (or three years back, four years back, etc) are used to break the tie.

PROCEDURE FOR AWARDING OF WAIVER CLAIM (TIME OF THE YEAR):

1. Beginning on the day after the conclusion of the MLB regular season and up through the first 30 days of he MLB regular season, the previous season's MLB standings are used to determine waiver claim priority. 

2. Beginning on the 31st day of the MLB regular season through the conclusion of the MLB regular season, the MLB standings as of 9 AM (Eastern) on the day the player clears waivers are used to determine waiver claim priority, with the previous season's MLB standings only used to break ties.

PROCEDURE FOR AWARDING WAIVER CLAIM (WAIVER PERIOD)

Beginning in 2022, if a player has been claimed off Outright Assignment Waivers by a club within a given waiver period and then sometime later in that same waiver period the same player is placed on Outright Assignment Waivers by another club, the club that claimed the player previously in that waiver period will have last (worst) waiver claim priority if that player is placed onto Outright Assignment Waivers again in that waiver period. 
NOTE: If more than one club claimed the player off Outright Assignment Waivers previously in a waiver period, the waiver claim priority for that club or those clubs the next time the player is placed onto Outright Assignment Waivers in that waiver period would be at the bottom of the waiver claim priority list, sorted by the previous season's standings beginning on the day after the conclusion of the MLB regular season through the 30th day of the MLB regular season, and the MLB standings as of 9 AM (Eastern) on the day the player clears waivers beginning on the 31st day of the MLB regular season through the conclusion of the MLB regular season.    

RESTRICTION ON MAKING WAIVER CLAIMS:

A club is not permitted to make a waiver claim and then trade the player to another club if the purpose or effect of the claim was to prevent a third club from being awarded the waiver claim. (A waiver claim that is judged by the MLB Commissioner to have been made for this purpose will be revoked, and the MLB Commissioner can invoke additional penalties against one or both of the clubs involved in the shenanigans).
EXAMPLE: Team "A" claims player off waivers. Team "B" also claimed the player, but wasn't awarded the claim because it had a lower (worse) waiver claim priority than Team "A." Team "A" then trades claimed player to Team "C," which has a lower (worse) waiver claim priority than Team "B."   

If a club wishes to remove a player from its MLB Reserve List (40-man roster) and send the player to the minors, the club must first secure Outright Assignment Waivers.
CoViD-19 EXCEPTION: A minor league player added temporarily to an MLB Active List roster to replace a player who has been placed on the CoViD-19 IL can be removed from the club's MLB Active List roster and returned to the AAA affiliate's roster without having to be placed on waivers.  

Outright Assignment Waivers can generally be requested anytime in a given waiver period, and they are always irrevocable. 

The waiver price is $50,000 (formerly $20,000). 

Once secured, Outright Assignment Waivers remain in effect for a set period of time:

1. Seven days or until the end of the waiver period (whichever comes first) for Outright Assignment Waivers secured September 1st through the 30th day of the MLB regular season:

2. The entire waiver period for Outright Assignment Waivers secured starting on the 31st day of the MLB regular season through August 31st.

3. 72 hours if the player is on Optional Assignment to the minors or on a Disabled List.

A club does not have to outright a player to the minors after Outright Assignment Waivers have been secured.

RESTRICTIONS ON PLACING A PLAYER ON OUTRIGHT ASSIGNMENT WAIVERS: 

If Outright Assignment Waivers have been secured and are in effect, a player cannot be placed on Outright Assignment Waivers again until the final two days of the waiver period.

Beginning in 2019, if a player is claimed off Outright Assignment Waivers during the period of time beginning with the first day of Spring Training (the date pitchers & catchers report) through the final game of the MLB regular season, the player cannot be placed back onto Outright Assignment Waivers again for at least 48 hours or until he has spent at least one day on the claiming club's MLB Active List (whichever comes first), and if a player is claimed off Outright Assignment Waivers during the off-season (the period of time beginning with the day after the conclusion of the MLB regular season up until the first day of Spring Training), the player cannot be placed back onto Outright Assignment Waivers again for at least seven days. 

A player who has a "no trade" right (full or partial) must waive his "no trade" right before he can be placed on Outright Assignment Waivers.

PLAYERS ON CUBS MLB RESERVE LIST WITH "NO-TRADE" RIGHTS: (updated 6-16-2023)
Ian Happ, OF (full) 
Seiya Suzuki, OF (full) 
Dansby Swanson, INF (full) 
Jameson Taillon, RHP (partial)

Outright Assignment Waivers cannot be requested while a player is on an MLB Paternity Leave List, Bereavement/Family Medical Emergency List, Military List, Restricted List, Suspended List, Temporarily Inactive List, Voluntary Retired List, Ineligible List, or Disqualified List.   

INJURED PLAYERS 

1. If a player on an MLB or minor league Injured List is placed on Outright Assignment Waivers during the MLB regular season, he must be both eligible to be reinstated from the Injured List and healthy enough to play. If waivers are secured, the player must be reinstated from the Injured List within 72 hours. If a player on an MLB Injured List is placed on Outright Assignment Waivers after the conclusion of the MLB regular season and waivers are secured, the player must be reinstated from the Injured List within 72 hours. 
NOTE: If a player on an MLB or minor league Injured List is claimed off Outright Assignment Waivers but then cannot pass a physical with the claiming club, the claiming club can request that the MLB Commissioner rescind the waiver claim, return the player to his former club, and refund the $50,000 waiver claim fee. (The MLB Commissioner also has the right to invoke additional penalties against the club the placed the injured player on waivers). 

2. With one exception, an injured player or a player rehabbing from an injury who is unable to pass a team physical can be placed on Outright Assignment Waivers only during a period of time beginning on the day after the conclusion of the MLB regular season up until 2 PM (Eastern) on the fourth day after the final game of the World Series. 
NOTE: If an injured player or a player rehabbing from an injury is placed on Outright Assignment Waivers anytime after 2 PM (Eastern) on the fourth day after the final game of the World Series, is claimed by another club, but then cannot pass a physical with the claiming club, the claiming club can request that the MLB Commissioner rescind the waiver claim, return the player to his former club, and refund the $50,000 waiver claim fee. (The MLB Commissioner also has the right to invoke additional penalties against the club the placed the injured player on waivers). 
EXCEPTION: An injured player who has accrued less than three years of MLB Service Time in his career and who did not accrue any MLB Service Time the previous season, has not previously been outrighted to the minors, and who was not selected in the immediately-preceding Rule 5 Draft, can be placed on Outright Assignment Waivers beginning on the day after the conclusion of the MLB regular season up until 2 PM (Eastern) on the 17th day prior to MLB Opening Day. 

RULE 5 SELECTED & DRAFT-EXCLUDED PLAYERS

1. A Rule 5 "Selected Player" cannot be placed on Outright Assignment Waivers any earlier than 2 PM (Eastern) on the 25th day prior to MLB Opening Day. 

MLB RULE 5 SELECTED PLAYERS ON CUBS MLB RESERVE LIST (updated 3-12-2021): 
NONE AT THIS TIME

2. A Rule 5 "Draft-Excluded Player" cannot be placed on Outright Assignment Waivers anytime after 2 PM (Eastern) on the fourth day after the final game of the World Series up until 2 PM (Eastern) on the 25th day prior to MLB Opening Day. 

MLB RULE 5 DRAFT-EXCLUDED PLAYERS ON CUBS MLB RESERVE LIST (updated 11-14-2023): 
Michael Arias, RHP (see NOTE)
Porter Hodge, RHP (see NOTE)
Bailey Horn, LHP (see NOTE)
Luke Little, LHP   
Luis Vazquez, INF (see NOTE)
NOTE: Once Draft-Excluded Player status is removed, Arias, Hodge, Horn, and L. Vazquez can be placed onto Outright Assignment Waivers even if he is injured up until 2 PM (Eastern) on the 17th day prior to 2024 MLB Opening Day.

Outright Release Waivers are irrevocable and cannot be withdrawn once they are requested.

While a player claimed off Outright Assignment Waivers costs $50,000 (formerly $20,000), a club can claim a player off Outright Release Waivers for the minuscule sum of $1. However, a club that claims a player off Release Waivers is responsible for paying 100% of the player's remaining salary, whereas if the same club waits until the player clears Release Waivers, the club can sign the player for the MLB minimum salary (or prorated portion of the MLB minimum salary), with the player's former club responsible for the balance.

A player who is claimed off Outright Release Waivers has the option to decline the assignment and become a free-agent (he has up to five days to decide). For most players, refusing an Outright Release waiver claim means the player's contract is terminated with no severance and his former club owes him nothing (same as an Article XX-D minor league FA who refuses an Outright Assignment), but for a player with "no trade" rights who refuses an Outright Release waiver claim, the player is owed his full salary for the balance of the contract, same as if he had not been claimed.

A player on an MLB Reserve List (40-man roster) who is released during the period of time extending from MLB Opening Day through August 31st cannot be added back to the MLB Active List of the club that released the player for at least 30 days - UNLESS - the MLB Active List of the club that released the player has at least one open slot during the period of time beginning when the player is released and extending up until the released player is re-signed and added back to the club's MLB Reserve List, and a player on an MLB 40-man roster who is released anytime during the period of time extending from September 1st to MLB Opening Day cannot be added back to the MLB 40-man roster (or MLB Active List) of the club that released the player until May 15th. 
NOTE:: While an unsigned player under club control who is not tendered a contract for the next season ("non-tendered") becomes a free-agent, it is not considered the same thing as an Outright Release, so a club can re-sign a non-tendered player to a Major League contract (or minor league contract) without any restrictions anytime after the player is non-tendered. Thus, the MLB contract tender date is a sort of roster "island oasis" in the middle of the off-season where a club can drop a player from its MLB Reserve List (including injured players) without having to worry about waivers or restrictions on off-season outright assignments or Outright Release.

A player on an MLB Reserve List (40-man roster) signed to a non-guaranteed contract who is released more than 15 days prior to Opening Day receives 30 days salary as termination pay (paid at the "minor league rate" if the player is signed to a "split contract"), and a player on an MLB Reserve List signed to a non-guaranteed contract who is released 15 or fewer days prior to Opening Day receives 45 days salary as termination pay (all players paid at the "Major League rate"). A player on an MLB Reserve List signed to a non-guaranteed contract who is released prior to MLB Opening Day receives 100% of his salary as termination pay if he is released while he is unable to render service due to an injury or illness suffered while under contract to the club.     
NOTE: Beginning in 2022, a player eligible for salary arbitration who signs a contract prior to an arbitration hearing will receive 100% of his salary if he is released prior to MLB Opening Day (although salary liability for former club would be partially offset by the pro-rated MLB minimum salary if the player signs an MLB contract with another club after being released).  

A player on an MLB Reserve List who is released during the MLB regular season receives 100% of his salary as termination pay (paid at the "minor league rate" for players on Optional Assignment to the minors).

An unsigned player on an MLB Reserve List released during the off-season receives no termination pay.

An MLB Rule 5 Selected Player (a player who was selected in the MLB Rule 5 Draft) cannot be released until restrictions have been removed, and if Rule 5 restrictions have been removed and the player is released, the player's termination pay is always paid at the "Major League rate" as long as he is released prior to being outrighted to the minors.

Outright Release Waivers cannot be requested on a player while he is on the Bereavement List, Military List, Suspended List, Disqualified List, or Ineligible List. 

A club cannot option a player signed to a "split contract" to the minors if the purpose of the assignment is to release the player and avoid paying termination pay at the "Major League rate."

A player is automatically & immediately removed from his club's Reserve List (40-man roster) and Active List when placed on Outright Release Waivers.