Keuchel opted out of his contract with the Twins on Tuesday, Britt Ghiroli of The Athletic reports.
Keuchel signed a minor-league deal with the Twins in late June, and he will now enter the open market after failing to receive a promotion to the majors. The 35-year-old southpaw put up a 1.13 ERA and 1.25 WHIP through 32 innings over six starts with Triple-A St. Paul.