Leyson Septimo (shoulder) has been assigned to Triple-A Charlotte to begin his rehab assignment. Septimo hasn't pitched since March 7 due to a strained left shoulder. The 27-year-old lefty is out of minor league options, so the White Sox will have to find room for him on the major league roster once his rehab assignment is up, or risk exposing him to waivers. He posted a 5.02 ERA and 14/6 K/BB ratio over 14 1/3 innings with the White Sox in 2012.