Millwood has agreed to a minor-league deal with Red Sox.
Millwood, who last pitched with the Baltimore Orioles in 2010, has a record of 159-137 and a career ERA of 4.11 in 14 major league seasons. Last season, Millwood owned a 4-16 record with a 5.10 ERA and 132 strikeouts.
This spring, Millwood signed with the New York Yankees, but opted out of his contract after he was not called up to the major league roster following Spring Training.
Prior to his one-year stint in Baltimore, Millwood played four seasons with the Texas Rangers, going 48-46 with a 4.57 ERA and 528 strikeouts. He spent the 2005 season with the Cleveland Indians (9-11, 2.86 ERA, 146 K) and the 2003 and 2004 seasons with the Philadelphia Phillies (23-18, 4.34 ERA, 132 K).
Millwood spent the majority of his career with the Atlanta Braves, where he played from 1997 to 2002. In six years with the Braves, Millwood was 75-46 with a 3.73 ERA and 840 strikeouts in 168 games.