In MLB, extra innings are just extra full innings played until one team finishes an inning with the lead, but modern rules add an automatic runner at second base in regular-season extras while playoff extras stay “traditional” with empty bases.

Basic idea

  • A regulation MLB game is 9 innings; if the score is tied after 9, the game goes to extra innings.
  • In extra innings, teams keep alternating half-innings (away team bats, then home team bats), and the first time an inning ends with one team ahead, the game is over.
  • There are no ties in MLB regular-season or postseason games; they continue until someone wins (suspended games are a separate rare rules situation).

Regular-season extra innings (automatic runner)

Since 2020 (and made permanent starting in 2023), MLB uses an automatic runner on second base to begin each half-inning of extras in the regular season.

  • Starting in the top of the 10th, the batting team begins with a runner on second and no outs; the same applies to the bottom half and every inning after that (11th, 12th, etc.) until the game ends.
  • The runner is usually the player who made the last out in the previous inning (or a pinch-runner for that spot), so you don’t “burn” another plate appearance.
  • Any runs that automatic runner scores are unearned for the pitcher’s ERA, so pitchers aren’t penalized statistically for a runner they didn’t allow.

This rule is designed to shorten games, reduce marathon 15–20 inning nights, and protect pitching staffs, though it’s controversial among traditional fans.

Postseason and All-Star Game extras

The playoffs and All-Star Game use normal baseball in extras: no free runner.

  • In the postseason, extra innings start with the bases empty and nobody out, just like the first nine innings.
  • Teams just keep playing full innings under standard rules until someone wins, no special tie-break gimmicks.

This is meant to keep high‑stakes games “pure” and avoid a playoff series turning on a rule some see as gimmicky.

Strategy in extra innings

The automatic runner has changed late-game strategy in regular-season extras.

  • Managers debate bunting the runner to third vs. swinging away; the choice often depends on who’s batting and whether they’re the home or road team.
  • Bullpen and matchup decisions get sharper: who can handle inherited runner pressure, who induces ground balls, and how to manage double-play chances.
  • For the home team, one run wins, so they can play for a single run more aggressively than the visiting team, which often aims for a multi-run inning.

“Quick Scoop” recap

  • If tied after 9, you keep playing full innings until someone leads after a completed inning.
  • Regular season: every extra half-inning starts with a runner on second, and those runs are unearned for pitchers.
  • Postseason/All-Star: no free runner; everything starts clean, bases empty.

Information gathered from public forums or data available on the internet and portrayed here.