⚾ Baseball, explained
Bat-and-ball game where two teams of nine alternate hitting and fielding across nine innings to score runs.
What am I watching?
Baseball is a duel repeated over and over: one pitcher throwing to one batter, with eight fielders backing the pitcher up. The team on defense (in the field) tries to get three batters out; the team on offense (at bat) tries to hit the ball, reach the four bases, and come all the way around to home plate to score runs. When three outs are made, the teams swap roles. One turn at bat for each team is an inning, and a standard game is nine innings.
The core of every moment is the count — the running tally of balls and strikes on the current batter, shown on screen as something like 3-2. Pitches in the strike zone that the batter doesn't hit (or swings at and misses) are strikes; three strikes and the batter is out. Pitches outside the zone that the batter lets go are balls; four balls and the batter walks to first base for free. Everything else — the pitcher's choice of fastball or breaking ball, the fielders shifting position, the runner creeping off first base — flows from that count.
Watch for the situations that create tension: runners on base with two outs, a 3-2 count late in a close game, a manager walking to the mound to change pitchers. If you follow cricket, the mental model transfers well — think of the pitcher as a bowler who gets to choose every delivery, the strike zone as an invisible set of stumps, and a home run as a six that also scores every teammate already on base. Baseball returns to the Olympics at Los Angeles 2028, so international interest is climbing again.
How scoring works
A run is scored when a player on the batting team advances around all three bases and touches home plate without being put out. Batters become runners by hitting the ball into fair territory and reaching base safely, by walking (four balls), or by being hit by a pitch. Runners already on base advance when the batter hits the ball, on walks that force them forward, on stolen bases, and on wild pitches or errors.
The fastest way to score is the home run: a ball hit over the outfield fence in fair territory. The batter and every runner on base all score, so a home run with the bases loaded — a grand slam — is worth four runs, the most possible on one swing. Otherwise runs are usually built up piece by piece: a single, a stolen base, and a well-placed hit can manufacture a run without any big blow.
The team with more runs after nine innings wins. There are no draws in professional baseball: if the score is level after nine, the game goes to extra innings, played one inning at a time until one team leads after a completed inning. The home team bats second in each inning, so it always gets the final chance to answer — and if the home team leads after the top of the ninth, the bottom half isn't played at all.
- A run scores when a runner touches first, second, third and home without being put out.
- A home run (over the fence in fair territory) scores the batter plus every runner on base.
- A grand slam is a home run with the bases loaded — four runs on one swing.
- Three outs end a team's half of the inning; nine innings make a standard game.
- Four balls give the batter a free walk to first base; three strikes make an out.
- If the score is tied after nine innings, extra innings are played until there's a winner.
- The home team bats last, so it always has the final opportunity to score.
Formats
Nine-inning game
Extra innings
Seven-inning game
The rules
The field
Baseball is played on a field shaped like a quarter-circle fanning out from home plate. The infield is a diamond of four bases — home plate, first, second and third — with the pitcher's mound in the middle. Beyond the infield lies the grass outfield, ending at a fence or wall. Two foul lines run from home plate through first and third base out to the fence; a batted ball between the lines is fair and in play, while a ball outside them is foul.
Unlike most sports, the outfield dimensions are not fully standardized — every stadium's fence distances and wall heights differ, which is part of the game's character. The infield geometry, however, is fixed, with the bases set 90 feet apart.
Fair and foul territory
A batted ball is fair if it settles in fair territory in the infield, first touches ground in fair territory beyond the bases, or passes over the fence between the foul poles. The foul poles themselves are in fair territory — a ball that hits one is a home run.
Teams, positions and lineups
Each team has nine players on the field when defending: the pitcher, the catcher (crouched behind home plate), four infielders (first baseman, second baseman, shortstop, third baseman) and three outfielders (left, centre and right field). On offense, players bat in a fixed batting order set before the game; the order cycles continuously, so the player after the ninth hitter is the first hitter again.
Most professional leagues, including MLB, use a designated hitter (DH): a tenth player who bats in place of the pitcher, so pitchers can focus entirely on pitching.
Innings and outs
A game is divided into innings, each split into a top half and a bottom half. The visiting team bats in the top of the inning while the home team fields; they swap for the bottom. A team's half-inning ends when the defense records three outs, no matter how many runs have scored — there is no limit to how many batters can come up or how many runs can score before the third out.
A standard game is nine innings. If the home team is ahead after the visitors bat in the ninth, the game ends without the bottom half. If the game is tied after nine, play continues in extra innings until one team leads after a completed inning.
The count: balls and strikes
Every at-bat is governed by the count of balls and strikes, always stated balls first (a "3-2 count" means three balls, two strikes). The strike zone is the space over home plate roughly between the batter's knees and the midpoint of the torso, judged by the home-plate umpire.
A pitch is a strike if the batter swings and misses, if it passes through the strike zone untouched, or if the batter hits it foul with fewer than two strikes (a foul ball can never be a third strike, except on a caught bunt attempt). A pitch outside the zone that the batter doesn't swing at is a ball. Three strikes and the batter is out (a strikeout); four balls and the batter walks to first base. A full count — 3-2 — is the moment of maximum tension: the next in-zone pitch must be dealt with.
Hit by pitch
A batter struck by a pitch while making a reasonable effort to avoid it is awarded first base, the same as a walk.
Ways to get out
The defense gets outs in several main ways. A strikeout: three strikes on the batter. A flyout: a batted ball caught before it touches the ground, anywhere on the field, fair or foul. A groundout / force out: a fielder with the ball touches first base (or throws to a teammate on the base) before the batter-runner arrives; the same applies at other bases when a runner is forced to advance. A tag out: a runner touched with the ball (or the glove holding it) while not standing on a base.
Two outs on one play is a double play — most classically a ground ball turned second-base-to-first — and three outs on one play, the rare triple play, ends the inning instantly.
Tagging up
When a fly ball is caught, runners must return to touch their base before advancing. A runner who waits on the base until the catch and then sprints — tagging up — can legally advance, which is how a deep flyout can still score a run (a sacrifice fly).
The infield fly rule
With runners on first and second (or bases loaded) and fewer than two outs, an easy infield pop-up is ruled an automatic out even if dropped. This stops the defense from deliberately dropping the ball to trick runners into a cheap double play.
Baserunning
Runners advance counter-clockwise and only one runner may occupy a base. A runner may attempt to advance at almost any time the ball is live — most famously by stealing a base, sprinting for the next base as the pitcher delivers and beating the catcher's throw. Runners take a lead-off, stepping a few paces off their base before the pitch, and the pitcher can attempt a pickoff throw to catch them off the base.
Runners forced to advance (because the batter or a trailing runner needs their base) can be put out by a simple touch of the base; otherwise they must be tagged. A runner who overruns a base (except first base, which may be overrun on a straight-through sprint) can be tagged out.
Pitching
The pitcher delivers from the raised mound and must keep one foot on the pitching rubber when releasing the ball. Pitchers mix pitch types — fastballs, plus breaking and off-speed pitches like sliders, curveballs and changeups — varying speed, movement and location to disrupt the hitter's timing.
With runners on base, a pitcher who makes an illegal deceptive motion is called for a balk, and all runners advance one base. MLB also enforces a pitch clock: the pitcher must begin the delivery within a set time or a ball is added to the count (a violation by the batter adds a strike), which has significantly shortened games since its 2023 introduction.
Starters, relievers and the bullpen
Teams use one starting pitcher and then a series of relief pitchers from the bullpen. A pitcher removed from the game cannot return. The closer is the specialist reliever who protects a narrow lead in the final inning, earning a save.
Substitutions and the designated hitter
Substitutions are permanent: once a player is removed, they cannot re-enter the game. Managers use pinch hitters (a substitute batter), pinch runners and defensive replacements strategically, especially late in close games. The designated hitter bats in the pitcher's lineup spot; since 2022 the DH is universal across both MLB leagues.
Umpires and replay review
A crew of umpires officiates: the home-plate umpire calls balls and strikes, while base umpires rule safe or out on the bases. In MLB, managers can challenge many close calls (not ball-strike calls), which are then checked by video replay officials. Fair/foul boundary calls, home runs and force/tag plays are all reviewable.
Glossary — 35 terms
Stats decoded
| Stat | Unit | What it tells you |
|---|---|---|
| Batting average | hits/at-bat | Hits divided by official at-bats, written as a three-decimal figure like .300. Around .250 is league-average in the modern MLB; .300 marks an excellent hitter. It ignores walks and power, so it's now read alongside OBP and slugging. |
| On-base percentage (OBP) | ratio | How often a batter reaches base by any means — hits, walks and hit-by-pitches — per plate appearance. Roughly .320 is average and .400 is elite. Valued above batting average by analysts because avoiding outs is the offense's scarcest resource. |
| Slugging percentage (SLG) | total bases/at-bat | Total bases divided by at-bats, weighting doubles, triples and home runs progressively more than singles. It captures power: a .500+ slugger is a genuine threat to change a game with one swing. |
| OPS | OBP + SLG | On-base percentage plus slugging percentage — a quick one-number summary of a hitter's overall offense. An OPS around .700 is roughly average; .900+ is star level and 1.000+ is MVP territory. |
| Home runs (HR) | count | Total home runs hit. Forty in an MLB season is a top slugger's mark; the single-season record is 73 by Barry Bonds in 2001. The most glamorous counting stat in the sport. |
| Runs batted in (RBI) | count | Runs a batter drives home through hits, sacrifices and bases-loaded walks. A 100-RBI season traditionally marks a productive run-producer, though it depends heavily on teammates reaching base ahead of you. |
| Stolen bases (SB) | count | Bases taken by running during the pitch and beating the throw. A measure of speed and baserunning aggression; success rate matters too, since getting caught stealing wastes a precious baserunner. |
| Earned run average (ERA) | earned runs/9 innings | Earned runs a pitcher allows per nine innings pitched, excluding runs caused by fielding errors. Around 4.00 is league-average in MLB; under 3.00 is excellent and a sub-2.00 season is historic. |
| WHIP | (walks+hits)/inning | Walks plus hits allowed per inning pitched — how many baserunners a pitcher permits. About 1.30 is average; near or below 1.00 means the pitcher rarely lets anyone on base at all. |
| Strikeouts (K) | count | Batters a pitcher retires on three strikes. Often expressed as K/9 (strikeouts per nine innings), where 9+ indicates a true power pitcher. Strikeouts are prized because they yield outs with no batted-ball luck involved. |
| Saves (SV) | count | Games finished by a reliever while protecting a narrow lead under the save rule. The headline stat for closers; 40+ saves marks a dominant season in the role. |
| Wins above replacement (WAR) | wins | An all-in-one estimate of a player's total value — batting, baserunning, fielding and pitching — expressed as wins added versus a readily available replacement player. Roughly 2 WAR is a solid starter, 5+ is All-Star level and 8+ is an MVP season. |
| Fielding percentage | ratio | Successful defensive chances (putouts plus assists) divided by total chances including errors. A basic reliability measure for fielders, though it can't see balls a slow fielder never reaches. |
Quick answers
How many innings are in a baseball game?
A standard professional game is nine innings, and each inning gives both teams a turn to bat. If the score is tied after nine, the game continues into extra innings until one team leads after a completed inning — there are no draws. If the home team is already ahead after the visitors bat in the ninth, the final half-inning isn't played.
How does scoring work in baseball?
A team scores one run each time one of its players advances around first, second and third base and touches home plate without being put out. Batters get on base with hits and walks, and teammates' hits move them around. A home run — a ball hit over the fence in fair territory — scores the batter and every runner already on base at once. The team with more runs at the end wins.
What is the difference between a ball and a strike?
It depends on the strike zone, the space over home plate roughly between the batter's knees and mid-torso. A pitch in the zone that the batter takes, any pitch the batter swings at and misses, or a foul ball with fewer than two strikes is a strike; a pitch outside the zone that the batter leaves alone is a ball. Three strikes make the batter out, while four balls award a free walk to first base.
Why do teams intentionally walk a batter?
An intentional walk concedes first base to a dangerous hitter to face a weaker one instead, or to set up a force play at any base. It's most common with first base open and a game on the line. It's a calculated risk: you avoid the slugger's power but hand the offense a free baserunner.
How long does a baseball game last?
Since MLB introduced the pitch clock in 2023, an average game runs around two and a half hours, down from well over three hours before. The clock forces pitchers to deliver within a set time and batters to be ready, with a ball or strike added to the count as the penalty for delay. Extra-inning games run longer, though the automatic runner on second base in extras speeds up a result.
What is the World Series?
The World Series is MLB's championship: a best-of-seven final between the champions of the American League and the National League, played each October. The first team to four wins takes the title. Despite the name it's a North American competition — the international national-team event is the World Baseball Classic.
Is baseball in the Olympics?
Baseball has been in and out of the Olympic programme — it was dropped after Beijing 2008, returned at Tokyo 2020 (where Japan won gold), was absent at Paris 2024, and returns again at Los Angeles 2028 as one of the host city's added sports. Softball, its sister sport, follows the same on-off pattern and also returns at LA 2028.
How is baseball different from cricket?
Both are bat-and-ball games, but baseball has no wickets and no draws: the pitcher throws to a defined strike zone, the batter must run only on fair hits, and outs come from strikeouts, caught balls, tags and force plays at four bases. Innings are tiny compared with cricket — just three outs per team per inning, nine innings in total — so games finish in under three hours. Scores are far lower too: a typical MLB game ends around 4-3 rather than in the hundreds.