The Barnstormers' Web site announced the transaction on Thursday afternoon. The 31-year-old Rundles was 2-1 with a 3.02 ERA in eight starts. In his 47 2/3 innings, Rundles allowed 40 hits, 11 walks and struck out 40.
Rundles was selected by the Red Sox in the third round of the 1999 First-Year Player Draft when current executive vice president of baseball operations Dan Duquette was Boston's general manager.
Rundles played in the Minor Leagues with six different organizations from 1999-2007 and he appeared in eight games with Cleveland in '08 and one in '09. In nine games, he posted a 1.50 ERA and is the second left-handed starter the Orioles have signed in as many days, joining veteran Jamie Moyer.
Last year, Rundles appeared in 35 games with Triple-A Memphis, going 1-3 with a 1.80 ERA.