Pittsburgh, which has lost six consecutive games, scored four times in the first inning Tuesday against Kansas City starter Mark Redman (4-4) but failed to keep the lead behind very shaky pitching.
Pirates pitchers gave the Royals 11 walks and nine hits with the bottom third of the Kansas City lineup getting six of the hits. Pittsburgh starter Kip Wells (0-1) took the loss.
The Pirates' first-inning rally was highlighted by Craig Wilson's two-run home run to center. But the Royals chipped away, with a three-run Kansas City second doing much of the damage. Buck had a two-run double and scored on a DeJesus single in the rally.
The Royals took the lead with a two-run burst in the fourth inning with the lead run scoring on a double play.
Kansas City added two runs in each the fifth and eighth innings and the final Pittsburgh ran came on a ninth-inning home run by Jack Wilson.