The 1969 Reforms: A Lower Mound, Divisional Play and the Birth of the League Championship Series

By 4Baseball Staff · November 5, 2026 · 10 min read

How baseball answered the Year of the Pitcher: the mound cut from 15 to 10 inches, a smaller strike zone, four new clubs, two divisions per league and the first League Championship Series, with the scoring numbers that followed.

Baseball changed more in the winter of 1968-69 than in almost any other off-season of the twentieth century. The pitcher's mound was lowered from 15 inches to 10. The strike zone was redefined so that it covered less of the hitter. Four new teams joined, taking each league from ten clubs to twelve. Each league split into an East and a West division, and the winners of those divisions met in a new best-of-five League Championship Series before the World Series. Every one of those changes took effect for the 1969 season.

The reason was the 1968 season, which hitters had lost so badly that it is still called the Year of the Pitcher. Bob Gibson posted a 1.12 earned-run average, Denny McLain won 31 games, and Carl Yastrzemski won the American League batting title at .301, the lowest mark ever to lead a league. The figures in the historical record give the scale: major-league teams averaged 3.42 runs a game in 1968, and 4.07 in 1969.

This article explains each reform, what it was meant to do, and what the numbers of the following seasons show. Some of the changes were about scoring and some were about the structure of the season, and the two kinds are easy to confuse. For the background that led to 1968, see the article on expansion and the Year of the Pitcher. All figures come from the historical record through the 2025 season.

What 1968 looked like

Start with the problem. The historical team tables let us add up every club in both leagues for a season and divide by the number of team-games. The results for 1967 through 1970 show how far 1968 stood from the seasons on either side.

The numbers in 1968 are not a one-year accident. Scoring had been sliding for several seasons, and the historical tables put the American League at .230 and the National League at .243 in batting average that year. The league leaders show the effect more vividly. The AL earned-run champion, Luis Tiant, finished at 1.60, with Sam McDowell at 1.81 and Wilbur Wood at 1.87. In the NL, Gibson's 1.12 was followed by Bobby Bolin's 1.99. Pete Rose won the NL batting title at .335, while the third-place hitter in the AL race finished at .289.

The people who ran the game saw the same numbers, and the playing rules committee acted after the 1968 season. The rest of this article follows its decisions, one by one.

The mound drops from 15 inches to 10

The first change was the simplest to describe. The rule book had set the maximum height of the pitcher's mound at 15 inches above the level of home plate. It was widely believed that some parks built their mounds to the limit or past it, because a higher mound gives the pitcher a steeper downhill plane and more leverage. The 1969 rule lowered the maximum to 10 inches, which is where the rule book still stands.

Why does height matter? A pitcher who releases the ball from higher up gets a steeper angle to the plate, which makes the pitch harder to square up and easier to keep low in the strike zone. Cutting five inches reduced the effect. The change did not touch the distance from the rubber to the plate, which is still 60 feet 6 inches, and it did not make the pitcher's job impossible. It nudged the angle in the batter's favor.

The numbers cannot isolate the mound from the other changes made at the same time, but they move the way one would expect if pitches were easier to hit. Hits per team-game rose from 7.91 in 1968 to 8.37 in 1969, and the league batting average from .237 to .248. Home runs per team-game rose from 0.61 to 0.80, a 31 percent increase.

The strike zone shrinks

The second change was to the strike zone itself. Since 1963 the zone had run from the top of the batter's shoulders to the bottom of his knees, a large rectangle. For 1969 the committee redefined it to run from the armpits to the top of the knees. That is a smaller target, and a pitch that had been a strike at the letters or at the shins was now a ball.

The walk totals are the clearest fingerprint. Walks per team-game were 2.82 in 1968 and 3.45 in 1969, an increase of about 22 percent in a single season. A smaller zone forces pitchers to throw fewer borderline pitches, and borderline pitches that miss turn into balls. Strikeouts, by contrast, hardly moved: 5.89 per team-game in 1968, 5.77 in 1969, a drop of 2 percent. The hitters were still swinging and missing at about the same rate, and the extra offense came from putting more men on base and from making more contact on the pitches in the zone.

That is worth pausing on. The smaller zone did not make hitters better at avoiding strikeouts. It changed what the pitcher could throw for a called strike. If the goal had been fewer strikeouts, the numbers show no result. If the goal was more baserunners, the walk total shows one.

Four new clubs and a bigger league

The third change arrived without any debate over the rules. The National League added the Montreal Expos and the San Diego Padres, and the American League added the Kansas City Royals and the Seattle Pilots. That raised the number of major-league clubs from 20 to 24, and each league now had twelve teams.

Expansion contributed to the scoring recovery in a way that is hard to separate from the rules. Four new franchises meant roughly 100 additional roster spots, which meant that the average pitcher in 1969 was a little less accomplished than the average pitcher in 1968. The new clubs also performed as expansion clubs do. The Expos went 52-110 and the Padres went 52-110, and the Pilots finished 64-98, last in the AL West.

It is worth noting what expansion did to attendance. Total attendance rose from 23,102,745 in 1968 to 27,229,666 in 1969, an increase of about 18 percent. But with 24 clubs instead of 20, attendance per club went from about 1.155 million to about 1.135 million, a decline of about 2 percent. All of the growth in the total came from having more teams. The Seattle franchise lasted only one season in the city and moved to Milwaukee, where it became the Brewers, a reminder that expansion is not a guarantee.

Two divisions in each league

With twelve teams in a league, the committee decided that a single pennant race was no longer enough. It split each league into two divisions of six clubs. The American League East held Baltimore, Boston, Cleveland, Detroit, New York and Washington, and the West held California, Chicago, Kansas City, Minnesota, Oakland and Seattle. The National League East held Chicago, Montreal, New York, Philadelphia, Pittsburgh and St. Louis, and the West held Atlanta, Cincinnati, Houston, Los Angeles, San Diego and San Francisco.

The geography was not what a map would suggest. Atlanta and Cincinnati sat in the National League West, while St. Louis and Chicago sat in the East, which kept the Cardinals and Cubs together. The alignment followed old rivalries and travel patterns more than the compass.

The point of divisions was to create more races. A single pennant race in a twelve-team league would be settled by a few clubs and ignored by the rest by August. Two divisions meant that twice as many clubs had a title in sight. The price was that a team could win its division while a better team in the other division stayed home. The 1969 standings did not produce that case: the NL East winner, the Mets, finished 100-62, the West winner, the Braves, 93-69, and the Cubs, second in the East, 92-70. Later seasons did. In 1973 the Mets won the NL East at 82-79, while the Dodgers at 95-66 and the Giants at 88-74 in the West finished out.

The League Championship Series

The last piece was the postseason. Before 1969 the World Series was played between the pennant winners, with no round before it. Now the division winners in each league met in a best-of-five series, the League Championship Series, to decide the pennant. The format ran from 1969 through 1984 and became a best-of-seven in 1985.

The first two series were both sweeps. In the American League, Baltimore, 109-53 in the regular season, beat Minnesota 3-0. In the National League, the New York Mets, 100-62, beat Atlanta 3-0. The Mets then beat the Orioles 4-1 in the World Series, one of the most surprising results in the sport's history, given that the Orioles had won nine more games than anyone else in either league. The Mets themselves had finished 73-89 in 1968, so they gained 27 wins in a year.

Notice that nothing about the structure changed the identity of the finalists. Under the pre-1969 format, the best record in each league would have won the pennant. In 1969 that is the Orioles at 109-53 in the American League and the Mets at 100-62 in the National League, and the World Series pairing would have been the same. This is sometimes lost in the retelling: the new round did not alter the outcome of the first year, though it did add a round of games.

The leaderboards, year against year

Season totals are one view; the top of the leaderboard is another, because the extremes move first. The historical sheets for the two seasons give the following leaders across both leagues.

The hitting leaders all went up, the leading pitcher won fewer games, and the best earned-run averages rose. Home runs went up by five at the top and runs batted in by 31. Hits rose by 21. The one category that barely moved is strikeouts, which fits the league-wide figure above: McDowell led both years with 283 and 279.

Read the ERA lines with care. Gibson's 1.12 was the extreme of an extreme season, and the 1969 leaders were still excellent pitchers. Marichal's 2.10 and Bosman's 2.19 would have been strong numbers in most years of the preceding decade. What changed was the distance between the best pitcher and the league: in 1968 the NL ERA leader was almost two runs below the league figure of 2.99, and in 1969 the gap was about one and a half runs below 3.60. Reforms narrowed a gap, and they did not remove it.

Did the reforms work?

The numbers say yes, with qualifications. Runs per team-game went from 3.42 to 4.07, an increase of 19 percent, and then to 4.34 in 1970. League earned-run average went from 2.98 to 3.61 and then 3.88. The league leaders came back toward ordinary levels as well: in 1969 the NL ERA champion, Juan Marichal, finished at 2.10, and the AL champion, Dick Bosman, finished at 2.19. Pete Rose hit .348 for the NL batting title, and Harmon Killebrew hit 49 home runs and drove in 140 runs in the American League.

But the recovery was not smooth. The American League scored 4.09 runs per team-game in 1969 and 4.17 in 1970, then 3.87 in 1971 and 3.47 in 1972, a figure close to the 1968 level of 3.41. The National League peaked at 4.52 in 1970, then settled near 3.9. The American League adopted the designated hitter in 1973, and its clubs scored 4.28 runs per team-game that year.

So the reforms of 1969 did their immediate job. They did not hold the line for good, and baseball's run environment kept moving for decades afterward. Anyone who wants to see where it went next should read the article on the home-run surge of the late 1990s.

The legacy of the format

The 1969 structure survived for a generation. The two-division, four-team postseason ran from 1969 until the strike of 1994, when the World Series was cancelled. The realignment into three divisions per league and a wild card, planned for 1994, took effect in the 1995 postseason, and the League Championship Series became the second round rather than the first. See the strike article for how that happened.

One feature of the 1969 plan has always been argued over: a short series can undo a long season. The best record in the majors in 1969 belonged to the Orioles at 109-53, and they lost the World Series in five games. A best-of-five or best-of-seven series is a small sample, which is why the league's best team does not always win.

Common questions

How high is the pitcher's mound today? The rule book sets it at 10 inches above home plate, the figure adopted in 1969.

What was the strike zone before 1969? From 1963 through 1968 it ran from the top of the shoulders to the bottom of the knees. In 1969 it was redefined to run from the armpits to the top of the knees.

Why were there divisions in 1969? Each league grew from ten to twelve clubs, and the committee judged that a single race would lose interest. Two divisions gave more teams a title to chase.

Who played in the first League Championship Series? Baltimore and Minnesota in the AL, and the Mets and Atlanta in the NL. Baltimore and the Mets each won 3-0.

Did the reforms end the pitchers' dominance? For several years, yes. Runs per team-game rose from 3.42 to 4.07 in the first year. But scoring in the AL fell again by 1972, and the DH followed in 1973.

Where to go next

For the era before the reforms, read the expansion era and the Year of the Pitcher. For the years that followed, see the free agency era. To see how the divisions work today, read the guide to magic numbers, and to browse the standings, use the standings page.