|Official Baseball Rules
Copyright © 2017-2023 by the Office of the Commissioner of Baseball. All rights reserved.
3.01 The Ball
The ball shall be a sphere formed by yarn wound around a small core of cork, rubber or similar material, covered with two strips of white horsehide or cowhide, tightly stitched together. It shall weigh not less than five nor more than 5-1/4 ounces avoirdupois and measure not less than nine nor more than 9-1/4 inches in circumference.
No player shall intentionally discolor or damage the ball by rubbing it with soil, rosin, paraffin, licorice, sandpaper, emerypaper or other foreign substance.
PENALTY: The umpire shall demand the ball and remove the offender from the game. In addition, the offender shall be suspended automatically for 10 games. For rules in regard to a pitcher defacing the ball, see Rules 6.02(c)(2) through (6).
Comment: Should a ball come partially apart in a game, it is in play until the play is completed.
3.02 The Bat
(a) The bat shall be a smooth, round stick not more than 2.61 inches in diameter at the thickest part and not more than 42 inches in length. The bat shall be one piece of solid wood.
NOTE: No laminated or experimental bats shall be used in a professional game (either championship season or exhibition games) until the manufacturer has secured approval from Major League Baseball of his design and methods of manufacture.
(b) Cupped Bats. An indentation in the end of the bat up to 1-1/4 inches in depth is permitted and may be no wider than two inches and no less than one inch in diameter. The indentation must be curved with no foreign substance added.
(c) The bat handle, for not more than 18 inches from its end, may be covered or treated with any material or substance. Any such material or substance that extends past the 18-inch limitation shall cause the bat to be removed from the game.
NOTE: If the umpire discovers that the bat does not conform to (c) above until a time during or after which the bat has been used in play, it shall not be grounds for declaring the batter out, or ejected from the game.
3.02(c) Comment: If pine tar extends past the 18-inch limitation, then the umpire, on his own initiative or if alerted by the opposing team, shall order the batter to use a different bat. The batter may use the bat later in the game only if the excess substance is removed. If no objections are raised prior to a bat's use, then a violation of Rule 3.02(c) on that play does not nullify any action or play on the field.
(d) No colored bat may be used in a professional game unless approved by Major League Baseball.
3.03 Player Uniforms
(a) All players on a team shall wear uniforms identical in color, trim and style, and all players' uniforms shall include minimal six-inch numbers on their backs.
(b) Any part of an undershirt exposed to view shall be of a uniform solid color for all players on a team. Any player other than the pitcher may have numbers, and/or letters, insignia attached to the sleeve of the undershirt.
(c) No player whose uniform does not conform to that of his teammates shall be permitted to participate in a game.
(d) A league may provide that each team shall wear a distinctive uniform at all times, or that each team shall have two sets of uniforms, white for home games and a different color for road games.
(e) Sleeve lengths may vary for individual players, but the sleeves of each individual player shall be approximately the same length, and no player shall wear ragged, frayed or slit sleeves; and no pitcher shall wear sleeves that are white, gray, nor, in the judgment of an umpire, distracting in any manner.
(f) No player shall attach to his uniform tape or other material of a different color from his uniform.
(g) No part of the uniform shall include a pattern that imitates or suggests the shape of a baseball.
(h) Glass buttons and polished metal shall not be used on a uniform.
(i) No player shall attach anything to the heel or toe of his shoe other than the ordinary shoe plate or toe plate. Shoes with pointed spikes similar to golf or track shoes shall not be worn.
(j) No part of the uniform shall include patches or designs relating to commercial advertisements. Notwithstanding the foregoing or anything else in these Rules, a Club may license to third-party commercial sponsors the right to place their name, logos and/or marks on the uniform, provided that the patch or design is approved in advance by the Office of the Commissioner after consultation with the Players Association.
(k) A league may provide that the uniforms of its member teams include the names of its players on their backs. Any name other than the last name of the player must be approved by the Office of the Commissioner. If adopted, all uniforms for a team must have the names of its players.
3.04 Catcher's Mitt
The catcher may wear a leather mitt not more than thirty-eight inches in circumference, nor more than fifteen and one-half inches from top to bottom. Such limits shall include all lacing and any leather band or facing attached to the outer edge of the mitt. The space between the thumb section and the finger section of the mitt shall not exceed six inches at the top of the mitt and four inches at the base of the thumb crotch. The web shall measure not more than seven inches across the top or more than six inches from its top to the base of the thumb crotch. The web may be either a lacing, lacing through leather tunnels, or a center piece of leather which may be an extension of the palm, connected to the mitt with lacing and constructed so that it will not exceed any of the above mentioned measurements.
3.05 First Baseman's Glove
The first baseman may wear a leather glove or mitt not more than thirteen inches long from top to bottom and not more than eight inches wide across the palm, measured from the base of the thumb crotch to the outer edge of the mitt. The space between the thumb section and the finger section of the mitt shall not exceed four inches at the top of the mitt and three and one-half inches at the base of the thumb crotch. The mitt shall be constructed so that this space is permanently fixed and cannot be enlarged, extended, widened, or deepened by the use of any materials or process whatsoever. The web of the mitt shall measure not more than five inches from its top to the base of the thumb crotch. The web may be either a lacing, lacing through leather tunnels, or a center piece of leather which may be an extension of the palm connected to the mitt with lacing and constructed so that it will not exceed the above mentioned measurements. The webbing shall not be constructed of wound or wrapped lacing or deepened to make a net type of trap. The glove may be of any weight.
3.05 Fielding Gloves
Each fielder, other than the catcher, may use or wear a leather glove. The measurements covering size of glove shall be made by measuring front side or ball receiving side of glove. The tool or measuring tape shall be placed to contact the surface or feature of item being measured and follow all contours in the process. The glove shall not measure more than 13 inches from the tip of any one of the 4 fingers, through the ball pocket to the bottom edge or heel of glove. The glove shall not measure more than 7-3/4 inches wide, measured from the inside seam at base of first finger, along base of other fingers, to the outside edge of little finger edge of glove. The space or area between the thumb and first finger, called crotch, may be filled with leather webbing or back stop. The webbing may be constructed of two plies of standard leather to close the crotch area entirely, or it may be constructed of a series of tunnels made of leather, or a series of panels of leather, or of lacing leather thongs. The webbing may not be constructed of wound or wrapped lacing to make a net type of trap. When webbing is made to cover entire crotch area, the webbing can be constructed so as to be flexible. When constructed of a series of sections, they must be joined together. These sections may not be so constructed to allow depression to be developed by curvatures in the section sides. The webbing shall be made to control the size of the crotch opening.
The crotch opening shall measure not more than 4-1/2 inches at the top, not more than 5-3/4 inches deep, and shall be 3-1/2 inches wide at its bottom. The opening of the crotch shall not be more than 4-1/2 inches at any point below its top. The webbing shall be secured at each side, and at top and bottom of crotch. The attachment is to be made with leather lacing, these connections to be secured. If they stretch or become loose, they shall be adjusted to their proper condition. The glove can be of any weight. See Appendix 4 for diagram of glove dimensions.
3.07 Pitcher's Glove
(a) The pitcher's glove may not, exclusive of piping, be white, gray, nor, in the judgment of an umpire, distracting in any manner. No fielder, regardless of position, may use a fielding glove that falls within a PANTONE® color set lighter than the current 14-series.
(b) No pitcher shall attach to his glove any foreign material of a color different from the glove.
(c) The umpire-in-chief shall cause a glove that violates Rules 3.07(a) or (b) to be removed from the game, either on his own initiative, at the recommendation of another umpire or upon complaint of the opposing manager that the umpire-in-chief agrees has merit.
A Professional League shall adopt the following rule pertaining to the use of helmets:
(a) All players shall use some type of protective helmet while at bat and while running the bases.
(b) All players in Minor Leagues shall wear a double ear-flap helmet while at bat.
(c) All Major League players must wear a single ear-flap helmet (or at the player’s option, a double ear-flap helmet).
(d) All catchers shall wear a catcher’s protective helmet and face mask while receiving a pitch.
(e) All base coaches shall wear a protective helmet while performing their duties.
(f) All bat/ball boys or girls shall wear a double ear-flap protective helmet while performing their duties.
3.08 Comment: If the umpire observes any violation of these rules, he shall direct the violation to be corrected. If the violation is not corrected within a reasonable time, in the umpire's judgment, the umpire shall eject the offender from the game, and disciplinary action, as appropriate, will be recommended.
3.09 Undue Commercialization
Playing equipment including but not limited to the bases, pitcher's plate, baseball, bats, uniforms, catcher's mitts, first baseman's gloves, infielders' and outfielders' gloves and protective helmets, as detailed in the provisions of this rule, shall not contain any undue commercialization of the product. Designations by the manufacturer on any such equipment must be in good taste as to the size and content of the manufacturer's logo or the brand name of the item. The provisions of this Rule 3.09 shall apply to professional leagues only.
NOTE: Manufacturers who plan innovative changes in baseball equipment for professional baseball leagues should submit same to Major League Baseball prior to production.
3.10 Equipment on the Field
(a) Members of the offensive team shall carry all gloves and other equipment off the field and to the dugout while their team is at bat. No equipment shall be left lying on the field, either in fair or foul territory.
(b) The use of any markers on the field that create a tangible reference system on the field is prohibited.