MLB Official Baseball Rules, Annotated: The Playing Field (Part 2)

Hello, and welcome to part two in what we expect to be a 10 part series. If you haven’t already read part one, OBJECTIVES OF THE GAME, you’ll want to start there. 

2.0 – THE PLAYING FIELD

Section 2 of the rules and this annotated guide covers the playing field and is broken into 5 sections: the layout of the field, home base, the bases, the pitcher’s plate and the benches. Let’s look at the subsections in order.

2.01 Layout of the Field

The field shall be laid out according to the instructions below, supplemented by the diagrams in Appendices 1, 2, and 3.

The infield shall be a 90-foot square. The outfield shall be the area between two foul lines formed by extending two sides of the square, as in diagram in Appendix 1 (page 158). The distance from home base to the nearest fence, stand or other obstruction on fair territory shall be 250 feet or more. A distance of 320 feet or more along the foul lines, and 400 feet or more to center field is preferable. The infield shall be graded so that the base lines and home plate are level. The pitcher’s plate shall be 10 inches above the level of home plate. The degree of slope from a point 6 inches in front of the pitcher’s plate to a point 6 feet toward home plate shall be 1 inch to 1 foot, and such degree of slope shall be uniform. The infield and outfield, including the boundary lines, are fair territory and all other area is foul territory.

It is desirable that the line from home base through the pitcher’s plate to second base shall run East-Northeast.

It is recommended that the distance from home base to the backstop, and from the base lines to the nearest fence, stand or other obstruction on foul territory shall be 60 feet or more. See Appendix 1.

When location of home base is determined, with a steel tape measure 127 feet, 33⁄8 inches in desired direction to establish second base. From home base, measure 90 feet toward first base; from second base, measure 90 feet toward first base; the intersection of these lines establishes first base. From home base, measure 90 feet toward third base; from second base, measure 90 feet toward third base; the intersection of these lines establishes third base. The distance between first base and third base is 127 feet, 33⁄8 inches. All measurements from home base shall be taken from the point where the first and third base lines intersect.

The catcher’s box, the batters’ boxes, the coaches’ boxes, the three- foot first base lines and the next batter’s boxes shall be laid out as shown in the diagrams in Appendices 1 and 2.

The foul lines and all other playing lines indicated in the diagrams by solid black lines shall be marked with paint or non-toxic and non-burning chalk or other white material.

The grass lines and dimensions shown on the diagrams are those used in many fields, but they are not mandatory and each Club shall determine the size and shape of the grassed and bare areas of its playing field.

NOTE: (a) Any Playing Field constructed by a professional Club after June 1, 1958, shall provide a minimum distance of 325 feet from home base to the nearest fence, stand or other obstruction on the right and left field foul lines, and a minimum distance of 400 feet to the center field fence.

(b) No existing playing field shall be remodeled after June 1, 1958, in such manner as to reduce the distance from home base to the foul poles and to the center field fence below the minimum specified in paragraph (a) above.

The first subsection of section 2 dives into the dimensions of the infield and then builds on that to define the outfield—in so doing, it leaves some ambiguities. Note the use of the word “shall,” as in “the infield shall be a 90-foot square.” In statutory language “shall” is the equivalent of “must.” The infield must be a 90-foot square, the outfield must be the area between two foul lines formed  by extending two sides of the square, etc. You’ll note that while the distance from home base to the nearest obstruction in fair territory must be more than 250 feet, the 320 foot distance from home point to the foul lines and 400 foot distance to center field is merely preferable. A plausible argument could be made that a ballpark with 250 foot fences in left, center, and right would not be preferable, but would be legal. 

The rule laying out the dimensions of the “pitcher’s plate” and home plate provides fodder for discussion as well. The pitcher’s plate must be 10 inches above the level of home plate and the slope between a point six inches in front of that plate and six feet further towards home plate must be uniformly one inch per foot. So the rule looks at a six-foot section of the area starting six inches in front of the rubber and heading towards home plate and requires a uniform one inch per foot slope for a six-inch total drop. This leaves four inches of drop to be made up in the six-inch area immediately in front of the pitcher’s plate, and from home plate towards the pitcher’s plate 54 feet. 

With the area that must maintain the uniform one inch per foot slope being limited to just the six-foot section six inches ahead of the rubber, it would appear earthworks or hill forts could be legally constructed in that 53.5 foot area as long as the slope was maintained and the drop between the pitcher’s plate and home plate was maintained at 10 inches. Perhaps the construction of an enormous berm fully obscuring the view of the batter from the pitcher’s mound is proscribed elsewhere in the rule book, but taking this section as read, it would merely need to not interfere with the six foot slope measurement section. 

Next we have the desirability of the line from home base through the pitcher’s plate to second base running East-Northeast. More ballparks adhere to this rule than you’d think, in the American League eight ballparks can be said to have their home plate-pitchers plate-second base line roughly travel East-Northeast; in the National League, seven comply with the preference—so half of Major League Baseball ballparks can be said to roughly adhere to the East-Northeast orientation. 

In what is perhaps the least well-known aspect of this rule, the recommended distance from home base to the backstop and from the base lines to fences or other obstructions is 60 feet. In other words, foul territory in the area around the infield should be about 60 feet. This rule appears to be broadly adhered to by most parks, if for no other reason than placing the dugouts closer to the field would cause safety concerns. 

Finally, in a game of inches and milliseconds, the fact that the surface of the infield vis-a-vis grass and dirt and where one begins and the other ends is entirely left up to the club is surprising. It is surprising we have not seen more clubs experiment with extreme changes or a “turf shift” to slow down balls hit to one portion of the infield or another. 

2.02 Home Base

Home base shall be marked by a five-sided slab of whitened rubber. It shall be a 17-inch square with two of the corners removed so that one edge is 17 inches long, two adjacent sides are 81⁄2 inches and the remaining two sides are 12 inches and set at an angle to make a point. It shall be set in the ground with the point at the intersection of the lines extending from home base to first base and to third base; with the 17-inch edge facing the pitcher’s plate, and the two 12-inch edges coinciding with the first and third base lines. The top edges of home base shall be beveled and the base shall be fixed in the ground level with the ground surface. (See drawing D in Appendix 2.)

The rule outlining the dimensions for home base is pretty straightforward: five-sided piece of white rubber, 17 inches square with the back corners removed, set flush with the ground and oriented with the “point” aiming away from home plate. The effect of the plate’s placement is that if the plate was square, the foul lines would render the portions removed according to the rule in foul territory. 

Straightforward, and yet, impossible mathematically. It turns out that in order for the plate to have the dimensions and angles called for, the 12” sides would actually need to be 12.02” in order to meet at the proper angle. In addition, the top edges of the plate are to be beveled, but how beveled? And beveling itself involves shaving a right angle off of a squared-off surface, and thus changes the dimensions of the object being beveled. Should the measurements called for in the rule be to the top or bottom of the bevel? In other words, if you imagine the effect of the beveling of the top of home plate to be to create a tiny plateau that encompasses the top of the plate, would the 17-inch measurement be made just of that protruding portion or would it be made down to the base of the bevel? Or somewhere in between? Unsurprisingly, since the math itself doesn’t work, the rule does not get into those kinds of specifics.  

2.03 The Bases

First, second and third bases shall be marked by white canvas or rubber-covered bags, securely attached to the ground as indicated in Diagram 2. The first and third base bags shall be entirely within the infield. The second base bag shall be centered on second base. The bags shall be 15 inches square, not less than three nor more than five inches thick, and filled with soft material.

This rule has been subject to some upcoming changes—specifically the portion involving second base. The description is difficult to imagine, so we borrow from the official appendix’s diagram to illustrate:

Under the current rule, second base is centered on the intersection of the lines from the first and third bases. The effect is that second base is actually slightly out of line with the other base, as its center is in line with their outer edge. They’ve been experimenting in the minors with moving second base 13.5” in towards home plate to place its outer edge in line with the outer edges of the other two bases.

This is all well and good and appeals to our natural desire for symmetry, but there is yet another ambiguity, or rather confusing bit of drafting, hiding in this rule. Look at the sentence “The second base bag shall be centered on second base.” What the rule intends to convey is exactly what the diagram shows, that the bag is centered on the base lines. What it suggests is that the base and the bag are two separate things, and the former exists separate and apart from the latter. Thus, the bag lays on top of the base but is not itself the base—fun facts to wow your friends with. 

2.04 The Pitcher’s Plate

The pitcher’s plate shall be a rectangular slab of whitened rubber, 24 inches by 6 inches. It shall be set in the ground as shown in Diagrams 1 and 2, so that the distance between the pitcher’s plate and home base (the rear point of home plate) shall be 60 feet, 6 inches.

Another rule where the diagram fills in a lot of the gaps in drafting. The pitcher’s plate is set 60 feet, six inches from the rear point of home plate—but from which point of the pitcher’s plate? The diagram suggests the intention is for it to be from the part of the pitcher’s plate closest to home plate, but clear drafting would demand clarity in word as well as the visual aid. 

2.05 Benches

The home Club shall furnish players’ benches, one each for the home and visiting teams. Such benches shall not be less than twenty-five feet from the base lines. They shall be roofed and shall be enclosed at the back and ends.

We can end with a silly one. The home club has to supply benches to both clubs, fair enough. You can imagine there might be a competitive advantage to providing seating for your team but forcing the other team to stand through a three-hour game. Similarly, tricksters that might like to place the opposing team’s benches on the other side of the city are kept from doing so by the 25 foot limit from the base lines. They have to be roofed and enclosed at the back and ends—but in no other way do they need to be as comfortable as the home benches. The benches needn’t be of a sufficient size to seat the team, nor need they have floors, apparently. A simple addition of a requirement that the accommodations of the visiting dugout be comparable in all material ways to that of the home team would eliminate any potential for comfort-based gamesmanship in the dugouts. 

Conclusion

Section 2 of the rules, in conjunction with the official diagrams, does a good job laying out the basics of the field of play. If you had never witnessed a baseball game first hand and had to recreate one using only the rules, you’d get pretty darn close to the game as we know it. The issues would come up in the details—when you first tried to manufacture a home plate and found that the measurements didn’t quite add up or the first time a club started monkeying around with the ground between home plate and the pitcher’s mound to see what kinds of competitive advantages they could discover. If this section were a statute being considered for passage, our comments would mostly be cleanup and for avoidance of doubt. 

This is the second part of a 10-part series breaking down the Official Baseball Rules. Coming up in part 3 we’ll be talking about EQUIPMENT AND UNIFORMS.