David McCarty was a bit of an unusual player. He played three years with the Red Sox, from 2003 through 2005. He was picked up off of waivers in August of 2003 and played in 16 games down the stretch run between left field and first base. He was a pretty good hitter in that limited amount of time, hitting .407/.448/.630/1.078 with one home run.
The next year, McCarty began working on pitching. He pitched a few innings during Spring Training and made the team as a pitcher/backup first-baseman. He pitched left-handed so his versatility was highly valued. He hit .258/.327/.404/.731 in 89 games with four home runs. He also pitched in three games, going 3.2 innings with four strikeouts and one earned run. His ERA was 2.45. Despite the relative success, that was the only experiment with McCarty as a pitcher.
In 2005, McCarty only played in 15 games, hitting .500/.667/.500/1.167, but injuries ended his career.