Cahill (11-11, 3.92 ERA) allowed just two runs on four hits over seven innings of work en route to a 3-2 victory over the Dodgers in his last start. He is 1-2 with a 2.55 ERA in four starts against the Padres this year.
The Padres will counter with Edinson Volquez (10-10, 4.24), who has won three of his last four starts. Volquez gave up three runs in 5.2 innings in his last outing on Sept. 11 in a 6-4 victory over the Cardinals. He is 1-0 with a 2.70 ERA in three starts against Arizona this season.
Arizona is currently 11.5 games behind the Giants in the NL West, and is 4.5 games behind in the NL Wild Card race.
First pitch is set for 6:40 p.m. PT with coverage on Fox Sports Arizona and KTAR 620 AM.
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