In 1989, he won a career-high 19 games for the A's during a season which the A's won 99 games, more than any other team in Major League Baseball. After Davis (and reliever Rick Honeycutt) pitched in the only AL Championship Series game that the A's lost that year, Davis was originally scheduled to be the A's starting pitcher for Game Four of the 1989 World Series. When the Loma Prieta earthquake caused Game 3 to be delayed by ten days, Tony La Russa decided to re-use the winners of Games 1 and 2, Dave Stewart and Mike Moore, as the starting pitchers of Games 3 and 4; La Russa also penciled in Davis as the starting pitcher for Game 6, if necessary. La Russa's strategy worked: both Stewart and Moore won their games, and Davis, publicly angry at La Russa for the change, became a free agent at the end of the season.