The Royals announced on Tuesday that Mizerock's contract was not renewed and that Kuntz will become a special assistant to general manager Dayton Moore and an outfield and baserunning instructor.
Special assignments coach Eddie Rodriguez, who managed Team USA to the World Cup championship last month, will become the first-base coach. The new bullpen coach will be hired later.
Returning will be bench coach John Gibbons, third-base coach Dave Owen, hitting coach Kevin Seitzer and pitching coach Bob McClure.
Moore said that the Royals decided they wanted a bullpen coach with a pitching background. Mizerock was a former Major League catcher.
"John Mizerock has been a tremendous contributor to our organization, but from a philosophical change we wanted to have a pitching coach in the bullpen," Moore said. "Mizerock's expertise was in catching and we wanted a bullpen coach whose expertise was in pitching."
The Royals' relief pitchers finished last in the American League with a cumulative 5.02 ERA.
Mizerock, 48, had been in the organization since 1992 and managed at every level, compiling a 648-534 record in nine years while winning three league championships. He first joined the Major League staff in 2002 and, for 13 games that season, served as the Royals' interim manager between the terms of Tony Muser and Tony Pena. Mizerock, who had a 5-8 record in that role, also was one of the candidates for the job that went to Pena.
He returned to the Minor Leagues after the 2004 season for two years as a catching instructor and one year as the Class A Wilmington manager before returning to the Major League staff in 2008.
Moore said that Kuntz will spend time with the upper-level Minor League clubs and with the Royals when they are in Kansas City to instruct in outfield play and baserunning.
"I think our coaching staff, under Trey's leadership, did a tremendous job, battled through a lot of adversity and kept a very positive approach surrounding the direction of our team and we're delighted to have them back," Moore said.
Dick Kaegel is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.