This article is about Major League Baseball's business rules. For the rules of play, see Official Baseball Rules.
The Official Professional Baseball Rules Book governs all aspects of the game of Major League Baseball beyond what happens on the field of play. There are a number of sources for these rules, but they all ultimately are sanctioned by the Office of the Commissioner of Baseball. Examples of these rules are the Rule 5 draft (so-named for the applicable section of the rule book) and the injured list.
Other examples include:
the 5/10 Rule whereby players who have been with a club for 5 consecutive years and have been a major league player for 10 years cannot be traded without their consent.
the roster list rules (active and expanded rosters) which also determines who is eligible to play for a team in the playoffs and World Series
tie-breaking rules for deciding which teams go to the playoffs
implementing/enforcing the expanded playing rules issued to umpires which goes into much greater detail than the official baseball rules of play. These rules are described in the Umpire's Manual.
The below sections enumerate the numbered Major League Rules, both before and after Major League Baseball reorganized the minor leagues in advance of the 2021 season, as multiple rules were changed at that time. With the elimination of one-game playoffs in 2022, the tiebreaker rules were significantly modified, since all ties are now resolved by formula. The revised tiebreaker rules appear in the 2024 edition described below.
As most rules do not state what the penalty is for a violation, broad discretion is granted to the Commissioner of Baseball via Rule 50, "Enforcement of Major League Rules", which specifies "action consistent with the commissioner’s powers under the Major League Constitution".[1]
The Major League Rules begin with a note stating that whenever a provision of any of its rules conflicts with a provision in the Basic Agreement (collective bargaining agreement) negotiated with the Major League Baseball Players Association, the provision in the Basic Agreement "shall in all respects control".
The Rules are followed by an Acceptance; "The foregoing ... have been duly accepted by the Major League Clubs and the Leagues of the National Association."
There are then Attachments to the Rules (numbers refer back to Rule # above):
3—Minor League Uniform Player Contract
12—Notice to Player of Release or Transfer
52—Major and Minor League Territories
54—Standard Minor League Financial Disclosure
56—Standard Form Letter Establishing Player Development Contract
58—Minor League Facility Standards and Compliance Inspection Procedures
At the top of page 1, a bolded, fully capitalized statement indicates that where the rules conflict with the currently effective basic agreement with the Major League Baseball Players Association, the basic agreement controls.
Reserve Lists
Player Limits
Eligibility to Sign Contract, Contract Terms and Contract Tenders
First-Year Player Draft
Annual Selection of Players (known as the Rule 5 draft)