Parnell was released by the White Sox on Monday, Daryl Van Schouwen of the Chicago Sun-Times reports.
Parnell was signed to a minor-league pact in the beginning of June, but the right-hander got shelled in Triple-A -- in 13.1 innings of work, he allowed 17 earned runs on 25 hits. His MLB experience may give him some notoriety on the free-agent market, but his best days appear to be behind him.