David McCarty arrived at Ft. Meyers not only to compete for the role he played last year as a righthanded bat off the bench but for a job as a left-handed reliever. McCarty was scheduled to join a group of pitchers that includes Keith Foulke and Mike Timlin when the Red Sox held the first official workout for pitchers and catchers.

In August 2003, McCarty was claimed off waivers by the Boston Red Sox from the Oakland Athletics.

In May, McCarty lined a two-run triple to right field that gave the Red Sox a 5-3 lead. They went on to win by that score. Later in the month, he had entered the game in the eighth inning and hit a walk-off two-run home run against the Mariners in the bottom of the twelfth inning to give the Red Sox a 9-7 victory.

McCarty made three pitching appearances for the Red Sox in 2004. He appeared in 91 games and batted .258 and in three games on the mound, went 3 2/3 innings, gave up two hits and struck out four.