July 29, 2014 5:43 p.m. ET

At 240 pages, Major League Baseball's rule book is dense, and it is only growing denser. Last winter alone, the league added three new rules and amended six others—and that doesn't even count the two rules it has amended since this season began.

But for all its love of new legislation, MLB has shown little inclination to delete rules that have long ceased being relevant. As a result, the rule book has become baseball's version of the tax code, dotted with obscurities and oddities whose existence are unknown even to many players and managers.

On the off chance that "Official Rules of Major League Baseball" isn't on your summer reading list, here are five of the strangest rules that have survived.

Rule 6.07: How to Bat Out of Order

At a time when each team's batting order is displayed on massive stadium video boards, it would seem impossible to get away with batting a hitter out of turn. But Rule 6.07, which governs what happens when a player bats out of order, practically dares managers to try it.

If, for instance, a manager tries to sneak his cleanup hitter back to the plate when his No. 8 hitter is due up, umpires are explicitly instructed not to call attention to it. The move is only illegal if the opposing team appeals before the first pitch to the next batter, after which it becomes legal.

According to the website Retrosheet, which maintains box scores for every MLB game since 1914, there have been more than 100 instances of hitters batting out of order, both successfully and unsuccessfully. But the modern examples are mostly gaffes involving substitutions or incorrect lineup cards.

Even ex-manager Bobby Valentine, who once tried to sneak back into the New York Mets' dugout wearing a fake mustache and sunglasses after an ejection, never tried sneaking his best hitter back to the plate too soon. "For it to happen today," he said, "somebody really has to be asleep at the wheel."

Rule 3.13: Make Up Your Own Rules

The concept of ground rules appears to be straightforward. Every ballpark has its own set of rules defining which balls are home runs, which balls are in play and what happens on balls affected by certain obstructions, such as Wrigley Field's outfield ivy.

But Rule 3.13 gives the home manager a way to essentially make up his own ground rules, assuming the visiting manager agrees. If there is "an overflow of spectators on the playing field," the home manager can propose "any ground rules he thinks necessary."

It is hard to conceive of such a scenario in an era when fans on the field are subject to arrest. But in the 1903 World Series between the Pittsburgh Pirates and the Boston Americans, hordes of fans occupied parts of the outfield. According to baseball historian David Nemec, the two managers agreed to rule any fair ball hit into an overflow crowd a ground-rule triple. The rule helped Boston slug 16 triples in the series, which it won in eight games, a World Series record that still stands.

Rule 7.08i: You Can't Steal First Base

The word "travesty" appears only once in the rule book, and it has nothing to do with cheating. The offense in question is one that defies logic: stealing first base from second.

On Aug. 4, 1911, Washington Senators infielder Germany Schaefer stole second in an attempt to draw a throw from the catcher that would allow a teammate to score from third. When that failed, according to the Society for American Baseball Research, he went in reverse and stole first, just to elicit a throw.

Schaefer, whose legendary antics made him part-ballplayer, part-vaudeville act, wasn't the only player to attempt to steal first, but he was the last. At some point thereafter, MLB introduced Rule 7.08i, which deems a runner out if he "runs the bases in reverse order for the purpose of confusing the defense or making a travesty of the game."

The rule has upheld the integrity of baseball ever since.

Rule 8.05f: Please Face the Batter

The balk rule has always been inscrutable. But even pitchers who have a general idea of what constitutes a balk are baffled by the rule that says it is a balk if the pitcher delivers the ball "while he is not facing the batter." This isn't a ban on windups that twist pitchers away from the plate initially. It is essentially a ban on pitching with one's back turned to the hitter.

"How would you physically throw a pitch if you're not facing the batter?" asked pitcher Brad Mills, who was recently demoted from the Toronto Blue Jays to their Triple-A team. "I don't know what would technically qualify for that."

MLB historian John Thorn said the rule dates to the 1880s, before the creation of the pitcher's mound (there was a pitcher's box instead). To fool base runners, Thorn said, "Some pitchers were known to engage in windmill gyrations, run-ups, hopping and quick-pitch misdirections thrown straight from the shoulder while facing a base."

Rule 4.03: You Have to Play Fair

The Tampa Bay Rays will position their fielders just about anywhere to gain an edge. But even the team best known for its extreme defensive shifts thinks one idea is too radical to consider: stationing a fielder in foul territory. "No, I don't think we would do that," said Rays bench coach Dave Martinez, chuckling at the thought.

This is no laughing matter to MLB. Rule 4.03 expressly forbids teams from placing any player other than the catcher outside fair territory. Never mind that the last known rationale for such a strategy came in the 1870s, when the National League ruled infield grounders that started fair and then rolled foul to be fair balls. (According to Nemec, batters would deliberately hit the ball in such a way that it briefly touched fair ground before spinning off into foul territory for cheap singles.)

The rule stands as a warning to cuckoo managers everywhere—that is, assuming they have read every last line of the book, which some haven't. Valentine, a rare rule book connoisseur, said, "It's a tedious read."

Write to Brian Costa at [email protected]