"I want to thank Bill for all his hard work this year and contributions," Epstein said in Glendale, where he was watching an Arizona Fall League game. "I respect his decision and how he went about it. He gave us a heads up so we weren't caught by surprise and were able to plan for it a little bit.
"I have nothing but respect for [Mueller]," Epstein said. "That relationship is still good. He chose not to come back, and we respect that and appreciate his contributions and we're moving on."
Mueller told MLB.com that his departure was related to the team's decision to not retain assistant hitting coach Mike Brumley, who was also in his first season on the Cubs' coaching staff.
Because Mueller kept the Cubs posted, they already have asked for permission to interview a couple of candidates, Epstein said.
"We should be able to move pretty quickly," he said.
Epstein said the Cubs were not likely to promote one of their Minor League hitting coaches.
"I think we're going to end up with an experienced Major League coach, someone who has done the job as Major League hitting coach before," Epstein said. "We feel great about our hitting coaches in the organization but right now with [Anthony Iapoce] as the coordinator and the hitting coaches at each level, we like the setup that we have. For this opening, we'll look for someone who has done this job before and with young players."
Mueller, 43, joined new manager Rick Renteria's staff after spending 11 years in the Major Leagues from 1996-2006, winning the batting title in 2003 when he hit .326 for the Red Sox. He also was the Dodgers' interim hitting coach in the second half of 2007.
The Cubs finished the season 12th in the National League in runs (595) and average (.239) and ninth in OPS (.684), but both Rizzo and Castro bounced back under Mueller's guidance. Mueller had emphasized gaining a player's trust as being key.
"It's just us understanding the guy, knowing where he's at and then implementing the plan and improving and dissecting his weaknesses as well as his strengths and improving all those things," Mueller said earlier this season.
On Sept. 30, Epstein announced Brumley would not return, although there was the possibility that he could stay in the organization as a scout. That prompted questions as to whether Manny Ramirez would be considered as an assistant hitting coach after his brief stint at Triple-A Iowa as a player/coach.
"Manny has not decided to retire as of yet," Epstein said last week. "He did an outstanding job with the organization and we'll continue to stay in touch."