By Bruce Levine-

(CBS) The Cubs accepted the resignation of hitting coach Bill Mueller on Tuesday. After signing a two-year contract with an option for 2016 before last season, Mueller quit under less-than-perfect circumstances.

First and foremost, the Cubs didn’t perform up to management’s expectations on offense. The Cubs had an on base percentage of .300, the lowest in the National League. A free-swinging team that had as many as 12 rookies on the squad during the season, Cubs hitters also averaged 9.1 strikeouts per game, setting a single season franchise record for futility.  Leading the league in those two dubious areas alone was enough to give Mueller and his bosses pause after the season.

Then last Tuesday, the Cubs reassigned assistant hitting coach Mike Brumley. President of baseball operations Theo Epstein told the media that Brumley had been offered another job in the organization. This decision didn’t sit well with Mueller, who wouldn’t take the job last season until the Cubs allowed him to bring in Brumley. The two were close friends and shared a similar hitting philosophy.

Epstein and his front office were concerned about the swing-and-miss factor of numerous players — and not of Javier Baez, who struck out in 45 percent of his plate appearances in the last quarter of the season. Some of the veteran hitters on the club scoffed at the two hitting coaches’ teachings throughout the season, sources told 670 The Score.

Mueller’s exit brings the total to five hitting instructors who have been fired or moved out in the three seasons that Epstein has run the baseball operations department. It would appear that the next coach will have vast experience as a hitting instructor. Since firing Rudy Jaramillo in 2012, the team has hired hitting instructors with little or no big league experience as the main batting voice. This time around, the search will most likely be for a successful batting guru with a distinguished resume.

The door will still be open for longtime front office associate Manny Ramirez to become the assistant batting coach. That move will need  the sanction of the new hitting coach, of course. The Cubs brass was pleased with Ramirez’s interaction with the young players he was tutoring at Triple-A Iowa this past season when he was a player-coach.

Baez, Kris Bryant and Jorge Soler all raved about their time with the former home run hitter. Epstein said last week he would wait for Ramirez to decide if he was going to retire before approaching him on a job.

Bruce Levine covers the Cubs and White Sox for 670 The Score and CBSChicago.com. Follow him on Twitter @MLBBruceLevine.