On August 9, Braun strained the intercostal muscles around his oblique ribcage. That led to him missing a number of games, and shortening his swing for a few weeks. After returning, on September 25 he hit his first grand slam, delivering a 2-out, 2–2 pitch from the Pirates' Jesse Chavez into the left field bleachers of Miller Park in the bottom of the 10th inning, winning the game 5–1, and keeping the Brewers' 2008 postseason hopes alive. Braun became the first—and as of July 2018, the only—player to hit a walk-off grand slam at Miller Park. Three days later, Braun helped put the Brewers into the postseason for the first time since 1982, by hitting a go-ahead 2-run homer in the bottom of the 8th against the Chicago Cubs. The homer was the difference in the game, which gave the Brewers a one-game lead over the New York Mets for the NL wild card.