A History of the Playoff Format: From Pennant Winners to Twelve Teams

By 4Baseball Staff · November 5, 2026 · 11 min read

How the major-league postseason grew from two pennant winners to twelve teams: the 1969 divisions, the 1995 wild card, the 2012 wild-card game and the 2022 format, with real standings from each season.

For the first six decades of the modern World Series, getting into the postseason meant finishing first. The best record in each league was the whole qualifying process, and a club that won 100 games and finished second went home with nothing. Today twelve of the thirty clubs reach the playoffs, and a team can win 87 games, finish second in its division and still play for a championship. Every change between those two worlds was an argument about the same thing: how many teams should be able to win the sport's biggest prize, and how much a 162-game season should count.

This article follows the format through four turning points: divisions in 1969, the wild card in 1995, a second wild card in 2012 and the twelve-team field of 2022. Each section pairs the rule with the standings of a real season, taken from the historical record, so you can see what the change did to actual teams. For the mechanics of the current bracket, see how the MLB postseason works. This piece is the history behind it.

The pattern is easy to state. Each expansion of the field followed an expansion of the league, a change in the schedule or a labor stoppage, and each one made October larger and the regular season a little less decisive. Whether that is a good trade is the question at the end.

Before 1969: one pennant, one series

From the first modern World Series in 1903, the format was the simplest imaginable. The American League and the National League each crowned a pennant winner, the club with the best record, and the two met in a championship series. There were no divisions, no playoff rounds, and no way to enter October as a runner-up. The leagues had eight clubs each for decades, which meant a pennant winner had finished ahead of seven rivals, and the race itself was the drama.

When two clubs finished tied for first, the league arranged a short playoff to decide who went on. That happened rarely, and when it did the game or series became famous by itself. For a fan, the system had a clean logic: every game in September counted toward the only prize that mattered.

The leagues began to grow in the early 1960s. The American League went to ten clubs in 1961 and the National League followed in 1962, with the schedule lengthened to 162 games. A ten-team league still had one pennant winner, so a smaller share of clubs could reach the World Series than before. When four more clubs joined for 1969, bringing the total to 24, each league had twelve members, and the leagues responded by splitting each into two divisions.

1969: two divisions and a League Championship Series

The 1969 season introduced the structure that survives today: each league split into two divisions, and the two division winners met in a League Championship Series for the pennant. The new series was a best-of-five. The expansion clubs that made the change necessary were the Montreal Expos, the San Diego Padres, the Kansas City Royals and the Seattle Pilots, and the historical record shows how they fared in the first year: Montreal went 52-110, San Diego 52-110, Kansas City 69-93 and Seattle 64-98. The Pilots lasted one season in Seattle.

The sheet for 1969 shows a league with 24 teams, an average of 4.07 runs per team per game and 27,229,666 in total attendance. Its standings show what the new structure did. In the National League East, the New York Mets won 100 games and the Chicago Cubs 92, eight back. In the West, Atlanta won at 93-69, one game better than the Cubs' total. Each league now had two races instead of one, and the winners of each met in the new series.

Two things are worth noticing. The Mets, at 100-62, beat a 109-win Orioles team in the World Series, so the new format produced a surprise champion in its first year. And the runner-up in the NL East, the Cubs at 92-70, would also have finished second under the old system. Divisions did not rescue anyone in the first year. They created a structure that later changes would loosen.

From five games to seven: 1985

The League Championship Series stayed a best-of-five through the 1984 season. In 1985, both LCS rounds became best-of-seven, matching the World Series. The reasoning was ordinary: a five-game series is quick, and the LCS decides a pennant. A longer series gives the better team a bit more room to win, at the cost of more off days and a longer October.

The field stayed at four teams, so no extra club gained entry. What changed was how much a round could swing on a few pitches. A short series is a lottery with weights, and each added game moves the odds slightly toward the stronger club. The leagues would adjust the length of rounds more than once in the decades that followed.

The strike years: 1981 and 1994

Two work stoppages bent the postseason out of shape, and both matter to the history.

In 1981, a players' strike split the season into two halves. The leagues decided that the winner of the first half and the winner of the second half would meet in a divisional round before the League Championship Series. The extra round is the reason the Los Angeles Dodgers' record includes a 1981 division series against Houston that they won, three games to two, on their way to the championship. The format was widely criticized, because a club could have the best overall record in its division and fail to qualify, if it did not win either half. It was used once.

In 1994, another strike ended the season in August and the entire postseason was cancelled. No World Series was played. That season had been scheduled as the first of a new structure: three divisions in each league and a wild card. When play resumed in 1995, the new structure arrived with it.

1995: three divisions and a wild card

The 1995 season is the first with a wild-card team: the club with the best record among non-division winners in each league. The leagues had realigned into East, Central and West divisions, making three division winners per league, and the wild card was the fourth qualifier. The first round was a new Division Series, a best-of-five, followed by the best-of-seven LCS and World Series.

The 1995 sheet shows 28 clubs and about 144 games per club, because the season began late after the strike. Runs per team per game were 4.85, up more than three-quarters of a run from 4.07 in 1969. The season gives two clean examples of why people still talk about the wild card.

In the American League, the Yankees finished 79-65 and took the wild card. They had trailed Boston in the East, and they met the Seattle Mariners, the West winner at 79-66, in the Division Series, losing three games to two. Seattle had reached the Division Series only after a one-game playoff against the California Angels, who finished 78-67. That tiebreaker game is part of the historical record, which is why each club shows 145 games instead of 144.

In the National League, the West winner was the Los Angeles Dodgers at 78-66, and the Colorado Rockies took the wild card at 77-67. Both clubs reached the postseason, one game apart, from a division in which no club won 80 games. Under the two-division format of 1969 to 1993, only the division winner would have qualified.

Neither wild card won a series in 1995, and the champion was Atlanta, which had the best record in the National League. But the structure's real effect showed over the next few years. Two more expansion clubs, Arizona and Tampa Bay, joined in 1998 and brought the total to 30. In 1997 the Florida Marlins had become the first wild-card team to win a World Series, proving that a club that was not the best in its division could win it all. In 1998 the Chicago Cubs, led by Sammy Sosa in the middle of the home-run chase, reached the postseason as a wild card, a story told in the article on the single-season home-run record.

2012: a second wild card and a one-game round

In 2012, the leagues added a second wild-card team in each league. The two wild cards met in a one-game playoff, with the winner advancing to the Division Series. The rule created a new kind of drama: a 162-game season could be settled by a single afternoon.

The 2012 sheet shows the format at work. There were 30 clubs, about 162 games each and 74,859,268 in attendance. In the American League West, Oakland won the division at 94-68. The Texas Rangers finished one game behind at 93-69, which sent them to the wild-card game, and the Baltimore Orioles, also 93-69 and the other wild card, beat them 5-1 in a single game. Baltimore then lost the Division Series to the Yankees, three games to two.

In the National League, Atlanta (94-68) and St. Louis (88-74) were the wild cards, and the Cardinals won the one-game round 6-3. They then beat Washington 3-2 in the Division Series and lost the NLCS to San Francisco, four games to three. The Giants swept Detroit in the World Series, 4-0, and the sheet shows that team had won the NL West at 94-68.

The Rangers' case is the instructive one. A 93-win team lost its season in one game because it had finished a game behind a division winner, in a year when the wild-card round was sudden death. The second wild card had a clear purpose: it made the division title matter more. Under the old single wild card, only one of the two 93-win clubs would have reached the Division Series, and the other would have been out. With two wild cards and a one-game round, winning the division was worth a pass around that game.

One earlier note belongs here. In 2011, the last season with a single wild card, the St. Louis Cardinals qualified on the last day of the season and then won the World Series. Their home, Busch Stadium, is a standing reminder that the wild-card route can lead to a title.

2020 and 2022: sixteen teams, then twelve

The 2020 season was cut to 60 games, and the postseason expanded to sixteen teams for one year. Eight clubs per league entered, and the first round was a best-of-three. The Dodgers swept Milwaukee in that round (2-0), the Blue Jays lost to Tampa Bay (0-2) and the Dodgers eventually won the championship. The sixteen-team field was a one-year emergency measure and did not carry over.

The permanent change came in 2022 under a new labor agreement. The field became twelve teams, six per league: three division winners and three wild cards. The two division winners with the best records receive a first-round bye. The remaining four clubs play a best-of-three Wild Card Series, hosted entirely by the higher seed. Then come the best-of-five Division Series, the best-of-seven League Championship Series and the best-of-seven World Series.

The structure rewards division titles in two ways. The bye lets a top-two seed skip a round and set its pitching, and the home-field advantage in the wild-card round goes to the higher seed. The 2022 agreement also ended the one-game tiebreaker playoffs: ties for a playoff berth are settled by a formula, starting with the head-to-head record, so the extra 163rd game of earlier years has disappeared from the calendar.

The Dodgers' 2022 season shows the cost of the bye. They went 111-51, the best record in franchise history, received the first-round bye and lost the Division Series to San Diego, three games to one. The bye is an advantage, not a guarantee, and the debate over whether a long layoff helps or hurts is unresolved. The best that can be said is that top seeds have won plenty of titles and lost plenty, and the sample is too small to settle it.

The field in numbers

The simplest way to see the expansion is as a share of the league that qualifies.

The club counts for 1969 (24) and 1995 (28) come from the historical sheets. The share of clubs that reach October has more than tripled since the sixteen-team pennant system, from one in eight to two in five. The 2020 field of sixteen was a one-year exception, and the ten-team field of 2012 returned for 2021.

The arguments

Defenders of the larger field make three points. More teams in the race keeps more cities engaged into September. The wild card gives a very good second-place team a chance that a pennant system would deny. And a short series is already a lottery, so a twelve-team field adds only one more layer of luck to a process that already includes plenty.

Critics make three counterpoints. Every addition reduces the premium on a great regular season: a club that wins 100 games is exposed to the same short-series risk as a club that wins 87. A larger field also lets more mediocre teams in, which means that a champion may be hard to defend as the best club of the year. And each round adds games, which lengthens the postseason and pushes the World Series later into the autumn.

The evidence is mixed. The wild-card era has produced champions that were excellent and champions that were merely good. The sheet cannot say who deserved what. What it can show is that every change in the format has been followed by a debate that had already happened in the previous generation.

Common questions

When did divisions begin? In 1969, when both leagues split into East and West divisions after expansion to 24 clubs.

When was the first wild card? In 1995. The 1994 postseason had been cancelled by a strike, so the three-division, wild-card structure first operated in 1995.

How many teams make the playoffs now? Twelve, six in each league, as of the 2025 season. Check MLB's official site for the current rules.

Why was the 2012 wild-card game added? It added a second wild-card team and gave division winners a reward for finishing first, since the wild cards would have to survive a one-game round.

What was the 1981 split season? A strike divided the year into two halves, and the winners of each half met in an extra divisional round. It was used for one season only.

Where to go next

For the mechanics of the current bracket, read how the MLB postseason works, and for the championship series itself, see the history of the World Series. A famous October moment from the divisional era is told in the 1988 World Series. To see how the race stands today, visit the standings and the schedule.