A Beginner's Guide to Major League Baseball
What Major League Baseball Is
Major League Baseball (MLB) is the top professional baseball league in North America and one of the oldest organized sports leagues in the world, with roots stretching back to the 19th century. Today it is made up of 30 teams, 29 based in the United States and one, the Toronto Blue Jays, based in Canada. The league is split into two halves that carry a lot of history: the American League (AL) and the National League (NL). Each league contains 15 teams, which are further divided into three divisions of five teams each, labeled East, Central, and West.
For most of MLB history the two leagues played by slightly different rules. The most famous difference was the designated hitter (DH), a player who bats in place of the pitcher. The American League adopted the DH in 1973, while the National League let pitchers hit for decades longer. That gap finally closed in 2022, when the DH became universal across both leagues.
How the Season Is Structured
The MLB regular season is a marathon. Each team plays 162 games from late March or early April through the end of September, usually in three or four game series against a rotating set of opponents. Because baseball is played almost every day, the season rewards depth and consistency rather than a single hot streak. A team can lose 70 games and still be one of the best in the sport.
Standings are tracked by wins and losses, and a common shorthand is games behind, which measures how far a team trails its division leader. The goal during the regular season is to win your division or to secure a wild card spot, which goes to the next-best teams that did not finish first.
The Playoffs and the World Series
Twelve teams reach the postseason: the three division winners from each league plus three wild card teams per league. The playoffs are a series of elimination rounds. It begins with the best-of-three Wild Card Series, followed by the best-of-five Division Series, the best-of-seven League Championship Series, and finally the World Series.
The World Series is the championship round, a best-of-seven showdown between the American League and National League pennant winners. The first team to win four games is crowned champion. In 2025 the Los Angeles Dodgers won the World Series in a dramatic seven-game series against the Toronto Blue Jays, becoming the first team in a quarter century to repeat as champions. Moments like that, decided in extra innings of a Game 7, are exactly why fans call the World Series the Fall Classic.
Key Stats to Know
Baseball is famous for its statistics, and a handful of numbers will help any newcomer follow the action. For hitters, the classics are:
- Batting average (AVG) - the rate of hits per at-bat; .300 or higher is excellent.
- Home runs (HR) - balls hit out of the field of play for an automatic run.
- Runs batted in (RBI) - runs a hitter drives home with their plate appearances.
- On-base plus slugging (OPS) - a modern combined measure of getting on base and hitting for power.
For pitchers, watch for:
- Earned run average (ERA) - runs allowed per nine innings; lower is better.
- Strikeouts (K) - batters retired on three strikes.
- WHIP - walks and hits allowed per inning pitched, a measure of how many runners a pitcher lets on base.
The Flow of a Game
A game is divided into nine innings, and each inning has two halves. The visiting team bats in the top half and the home team bats in the bottom half. A team stays on offense until it records three outs. The team with more runs after nine innings wins; if the score is tied, the game continues into extra innings until someone comes out ahead, so baseball has no clock and no guaranteed ending time.
The core confrontation is between the pitcher and the batter. The pitcher tries to throw strikes the batter cannot hit cleanly, while the batter tries to put the ball in play and reach base. Around that duel is a rich layer of strategy: stolen bases, defensive shifts, bullpen management, and pinch hitting all shape how a game unfolds.
Why Fans Love It
Baseball rewards patience and attention to detail. Because the season is so long, it becomes part of daily life for millions of fans from spring through fall. The lack of a clock means no lead is ever fully safe, and the one-on-one nature of pitcher versus batter gives every pitch its own drama. Whether you are drawn in by the numbers, the history, or the tension of a late-inning rally, MLB offers a deep and rewarding game once you learn its rhythms.
