In anticipation of the move, the team optioned utility infielder Tug Hulett to Triple-A Omaha after Sunday's 6-3 win over the White Sox.
Buck was back in the Royals' clubhouse before Sunday's game. He said he felt good and was glad to be back in Kansas City.
Buck hasn't played since May 30, when he left a game against the White Sox with a herniated disk in his back. He's been on the disabled list ever since.
Buck hit .259 with two homers during a seven-game rehab assigment with Omaha. He caught nine innings in back-to-back games on Thursday and Friday.
Buck, who has shared the catching duties with Miguel Olivo during the last two seasons, is hitting .226 with three homers and 19 RBIs in 28 games with the Royals.
Rustin Dodd is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.