Jackson missed most of the 1918 season while working in a shipyard because of World War I. In 1919, he came back strongly to post a .351 average during the regular season and .375 with perfect fielding in the World Series. However, the heavily favored White Sox lost the series to the Cincinnati Reds. The next season, Jackson batted .382 and was leading the American League in triples when he was suspended, along with seven other members of the White Sox, after allegations surfaced that the team had thrown the previous World Series.