The right-handed Hughes has struggled throughout the season, compiling a 4-13 record and a 4.91 ERA. He hasn't won a start since July 2, and he's lost 11 of his last 13 decisions.
Hughes was knocked around for five runs -- three earned -- over 4 2/3 innings in a loss against Toronto on Monday. Pettitte, on the other hand, threw seven shutout innings in a win over the Blue Jays on Tuesday.
Josh Vitale is an associate reporter for MLB.com.
This story was not subject to the approval of Major League Baseball or its clubs.