Bako made his major league debut with the Tigers on April 30, 1998, going 0-for-4 with three strikeouts. His first Major League hit, a bases loaded double, came the next day off Bill Swift, when he went 2-for-5 against the Seattle Mariners in a 17–3 Tigers win. He hit his first major league home run on May 15 against the Oakland Athletics; it came off Mike Mohler in the bottom of the sixth inning with two runners (Damion Easley, Joe Randa) on base. He also went 4-for-4 against the New York Yankees on July 21. Bako's rookie season was arguably his most successful: he posted a .272 batting average, hit three home runs, batted in 30 runs, and collected 106 total bases. After the season, the Tigers traded Bako to the Houston Astros in a seven-player deal that included Brad Ausmus.