What Is a Walk-Off in Baseball?

Bottom of the ninth, tie game, a runner on second. The batter lines a single into the gap, the runner rounds third and slides home, and before the ball is even back to the infield the home dugout has emptied onto the field. The game is over the instant that run scores. No bottom-of-the-inning cleanup, no final out. That sudden ending is a walk-off.

The core idea

A walk-off happens when the home team scores the winning run in its last at-bat and the game ends immediately. Because the home team always bats last, it can win the moment it takes the lead in the bottom of the ninth or in any extra inning. There is no reason to keep playing once the home team is ahead with no more turns for the visitors.

That is the key difference from every other run in the game. Normally an inning finishes on outs. A walk-off run ends the game the second it crosses the plate.

Why only the home team

Baseball’s batting order between the two teams is fixed: the visiting team bats in the top of each inning, the home team in the bottom. If the visitors take the lead in extra innings, the home team still gets to respond in the bottom half. The home team’s rally is the last word, so only it can end the game with a hit.

The visiting team can absolutely win in extras. It just cannot do so on a walk-off, because its lead is never the final event of the inning.

Types of walk-offs

A walk-off is defined by the result, not the method. Any play that pushes the winning run home in the bottom of the final inning qualifies.

Walk-off type	How the run scores
Walk-off home run	Batter hits it out; the game ends as he rounds the bases
Walk-off hit	A single, double, or triple drives in the winning run
Walk-off walk	Bases loaded, the batter draws a walk, forcing in the run
Walk-off hit by pitch	Bases loaded, the batter is hit, forcing in the run
Walk-off error / wild pitch	A defensive mistake lets the winning run score
Walk-off sacrifice fly	A fly ball is caught, and the runner tags up and scores

The most dramatic is the walk-off home run, sometimes called a walk-off “grand slam” if the bases are loaded. But an unglamorous bases-loaded walk ends the game just as completely.

One rule detail on the home run

A walk-off home run still has to be legal. The batter and any runners ahead of him must touch all their bases in order. On a game-ending homer, only the runners needed to win have to score, but the batter who hit it out is credited with the home run only if he completes the trip around the bases. In practice players do circle the bases through the celebration for exactly this reason.

The walk-off is one of the reasons baseball has no clock. Because the home team is guaranteed its final at-bat, a game is never truly over until the last out or the winning run, and that is what makes the bottom of the ninth the tensest half-inning in the sport.