The last time Josh Harrison hit a walk-off homer, he was a high school senior in Cincinnati. The game was played in front of a few dozen people on a spring afternoon. Still the only homer of his prep career remains ingrained in Harrison's memory. Now it's got company. The Pittsburgh Pirates utility infielder sent a fastball from Miami reliever Mike Dunn into the first row of seats in right-center leading off the ninth, the improbable homer lifting the Pirates to a 4-3 victory on Tuesday night.