Keller will start Opening Day against the Rangers on April 1, Josh Vernier of 610 Sports reports.
Keller avoided arbitration with the Royals in January, and he'll take the mound for Kansas City to begin the regular season in the second Opening Day start of his career. The right-hander has made three Cactus League starts this spring, allowing eight runs (six earned) on 15 hits and seven walks while striking out six over 9.1 innings.