How does the automatic runner work in extra innings?

Under Rule 7.01(b)(2) of the 2026 Official Baseball Rules, each half-inning after the ninth begins with a runner on second base.

• The runner is the player in the batting order immediately before that half-inning's leadoff hitter, or a pinch-runner for him. For example, if the number five hitter is due to lead off the tenth, the number four hitter (or a pinch-runner) starts on second.
• If the player immediately before the leadoff hitter is the pitcher, the runner may be the player before the pitcher in the order.
• The leadoff batter is whoever would have led off the inning without this rule.
• If the automatic runner scores, an earned run is not charged to the pitcher.
• The rule does not apply to Wild Card Series, Division Series, League Championship Series or World Series games, so postseason games are played without an automatic runner.

Sources: 2026 Official Baseball Rules, Rule 7.01(b) and 7.01(g); MLB, Designated Runner (mlb.com/glossary/rules/designated-runner).