The Orioles claimed Walker off waivers from Atlanta on Wednesday, Roch Kubatko of MASNSports.com reports.
Walker went from Baltimore to Atlanta via waiver claim less than a month ago, and he'll now head back to the Orioles. The left-hander holds a career 6.59 ERA and 31:14 K:BB over 27.1 innings covering parts of three big-league seasons. Walker does not have minor-league options remaining.