The Red Sox acquired outfielder Rajai Davis from the Athletics for minor league outfielder Rafael Rincones, the team announced Wednesday.
Davis, 36, is fourth in the AL with 26 steals this season. The Red Sox have the third most steals in the AL as a team.
This year he is batting .233 with a .294 OPB. For his career, Davis is hitting .264 with a .313 OPB.
Boston had a 4.5 game lead over the Yankees at the top of the AL East going into Wednesday.
Davis is in his 12th season and the Red Sox will be his fourth team over the last three years.