**MLB postseason extra-inning games remain possible as Division Series play continues with several tight matchups.** Traders assign roughly 87-90% implied probability to at least one game reaching 11+ innings, reflecting the competitive series scores and recent one-run contests, including Milwaukee’s walk-off wins over San Diego. Probability drops to around 58% for 12+ innings and lower for 13+ or beyond, consistent with historical postseason patterns where 18-inning marathons are rare but extra-inning affairs occur when bullpens dominate and offenses stall in high-leverage situations. The best-of-five and best-of-seven formats in the Division Series, League Championship Series, and World Series provide multiple opportunities for extended contests, particularly in evenly matched pitching duels or rivalry rematches. No extra-inning games have occurred through the Wild Card round or early Division Series games.