The 2023 Royals starting pitching staff had a 5.12 ERA, fourth-worst in baseball. It was a revolving door of starters - 29 different pitchers made a start, although to be fair many were “openers.” Only three starters tossed at least 100 innings, and only one starter with 10+ starts posted an ERA below four - mid-season pickup Cole Ragans.
Rather than wait around and hope some young arms would turn the proverbial corner, management decided to invest in the rotation through free agency. That can always be a dicey proposition between arm injuries and the decline of players once they hit age 30.