How the 2018 MLB Playoff Structure Worked
In 2018, the MLB playoff format featured ten teams across both leagues: five from each the American League and the National League. Each league had three division winners who earned automatic berths, plus two wild card teams. A Wild Card Game determined the final playoff spot in each league, followed by the Division Series, Championship Series, and World Series. Understanding this structure explains how teams reached the postseason and how matchups were determined that year.
League and Division Setup in 2018
Both leagues maintained three divisions—East, Central, and West—with five teams each. This alignment had been in place since 2013, when the Houston Astros moved from the National League Central to the American League West. The change created three divisions of five teams in each league and set the stage for a balanced playoff qualification process with division champions and wild card teams.
Qualifying Teams and Wild Card Process
For the 2018 playoffs, the top team in each division qualified automatically. Additionally, two wild card teams per league advanced based on the best win-loss records among non-division winners. A one-game Wild Card Game in each league determined the final playoff berth, adding a decisive, high-stakes match to the postseason calendar.
Wild Card Game Format
The Wild Card Game used the league’s best non-division winner to host the second-best non-division winner. Home-field advantage went to the team with the better regular-season record. This single-elimination game added drama and compressed the timeline, giving fans a quick, winner-take-all playoff showcase before the Division Series.
Division Series and Championship Series
Following the Wild Card Game, the Division Series (LDS) matched the division winner against the Wild Card Game winner or another division winner, depending on seeding. Each LDS was a best-of-five series. The winners advanced to the League Championship Series (LCS), a best-of-seven round that determined each league’s representative in the World Series.
| Stage | Format in 2018 | Series Length |
|---|---|---|
| Wild Card Game | One-game playoff | 1 game |
| Division Series | Matchup by seeding | Best-of-5 |
| Championship Series | Best-of-7 | Best-of-7 |
| World Series | Best-of-7 | Best-of-7 |
2018 Playoff Participants
In the American League, the Boston Red Sox, Houston Astros, New York Yankees, Cleveland Indians, and Oakland Athletics qualified. In the National League, the Los Angeles Dodgers, Milwaukee Brewers, Atlanta Braves, Chicago Cubs, and Colorado Rockies made the postseason. Each team’s path reflected the competitive balance of the 2018 season and the structure of the playoff format.
Key Notes on Home Field and Seeding
Seeding within the playoffs was based on regular-season records, with division winners typically holding higher seeds than wild card teams. Home-field advantage in the Division Series and LCS followed standard rules: the team with the better record hosted more games, which could include the Wild Card Game winner when applicable. These mechanics aimed to reward strong regular-season performance while preserving competitive balance.
Frequently Asked Questions: 2018 MLB Playoff Format
- How many teams made the 2018 playoffs? Ten teams total, five per league.
- Was there a Wild Card Game in 2018? Yes, one Wild Card Game in each league decided the final playoff berth.
- Did the 2018 format include a second Wild Card round? No, the second Wild Card round was not implemented until 2022.
- How were teams seeded in the Division Series? By regular-season records, with division winners generally seeded higher than wild card teams.
- Which teams reached the 2018 World Series? The Los Angeles Dodgers and the Boston Red Sox advanced to the World Series, with the Red Sox winning the championship.
Context and Evolution Beyond 2018
The 2018 playoff format represented a phase in MLB postseason structure that preceded the 2022 expansion to three wild card teams per league and a revised Wild Card Series. Understanding this era highlights how the format has evolved while showing the foundational elements—division winners, wild card teams, and best-of-round series—that have long defined MLB’s postseason. The 2018 format remains a useful reference point for comparing changes and continuity in the broader history of the playoffs.