Kansas City released Campau in June 1888, and he then signed with the Detroit Wolverines, a team that had won the National League pennant in 1887 but had lost its star right fielder, Sam Thompson, to injury. Campau made his major league debut on July 7, 1888, and appeared in 70 games in the outfield for Detroit. Campau proved to be a capable defensive replacement, compiling a .933 fielding percentage (16 points higher that the National League average) and contributing 10 outfield assists and 3 double plays. At the plate, Campau's major league debut was less auspicious as he compiled a .203 batting average. His speed continued to help his cause, as he stole 27 bases and had three triples and a home run. His 27 stolen bases led the team, and he was the recipient of a prize from a local business as the team's leading base-runner. Campau later expressed his gratitude to Detroit first baseman Dan Brouthers who he recalled was "like a father to me" in Campau's first major league season.