Reliever Yohan Pino was optioned to Triple-A Omaha in a corresponding roster move.
Holland, 29, has not pitched since April 17 when he suffered a right pectoral strain.
"He's fine and he's ready to go," Royals manager Ned Yost said of Holland. "We're just trying to give Chris Young an extra day of rest."
Holland has saved 40 or more games in each of the past seasons, and had four saves in four opportunities this season before being placed on the DL. His 46 saves in 2014 were second in the American League.
Holland, a two-time All-Star, re-joins a pitching staff that ranks in the top five in the major leagues in ERA, saves, and opponents' batting average. Kansas City’s bullpen ERA of 1.08 is by far the best in MLB.
Holland signed a one-year, $8.25 million in the off-season to avoid salary arbitration.
- Scooby Axson