SAN FRANCISCO — Giants manager Bruce Bochy has announced the worst-kept secret in San Francisco’s clubhouse: left-hander Madison Bumgarner will start Wednesday’s wild-card game against Pittsburgh or St. Louis.

Bochy said before Sunday’s regular-season finale against San Diego that he felt comfortable with Bumgarner or Jake Peavy on the mound. But given Bumgarner’s success the last few years, he said “I don’t think there was any question who you pitch that game.”

Bumgarner was 18-10 with a 2.98 ERA this season. He has a 3-2 record with a 3.79 ERA in six postseason starts, all during San Francisco’s runs to the 2010 and 2012 World Series titles.

Edinson Volquez (13-7) will start on the mound for the Pirates.

The winner of the wild-card game will face the Washington Nationals in a best-of-five division series.