NEW YORK -- Before the regular season ended, the Mets made certain that manager Terry Collins would receive no internal blame for the team's performance, exercising the 2013 option on Collins' contract. As a result, some responsibility fell to the coaching staff, which will have four new members next season.

Bench coach Ken Oberkfell, third-base coach Chip Hale, first-base coach Mookie Wilson and bullpen coach Jon Debus will not return to the Mets, making hitting coach Dave Hudgens and pitching coach Dan Warthen the lone holdovers on Collins' staff.

Tim Teufel and Ricky Bones will join the staff as third-base coach and bullpen coach, respectively.

"Those that are departing go with our thanks for their contributions last year," general manager Sandy Alderson said on a conference call Wednesday. "Sometimes changes are made for individual reasons. Sometimes they're made for the overall composition of the staff and how it fits together. But I think in the final analysis, [Collins and I] both agreed that changes were necessary for us to move forward."

Wilson and Debus will be offered other positions within the organization, though there are no guarantees that either will accept. Wilson, who was responsible for the team's outfield defense and baserunning, did not accept an alternate position under similar circumstances when the Mets dismissed him from the same position in 2002.

"I thought he did a tremendous job to be able to do both jobs this year," Collins said. "I know it was very, very difficult for him at times, but he did it with professionalism and a smile on his face. Wherever he ends up, I hope he understands that he's wanted here."

Given the coaching staff's composition, Alderson indicated that the Mets wanted someone with more Major League experience than Oberkfell serving as bench coach. And in the case of Debus, a catcher throughout his playing career, the Mets preferred to have more of a "pitching presence" in the bullpen. The club already employs multiple bullpen catchers.

The departure of Hale, who has spent the past six seasons on National League coaching staffs, changed the complexion of Collins' group. The Mets offered Hale a new contract, but he declined in order to become Bob Melvin's bench coach in Oakland -- a hiring the A's announced Wednesday.

"I know what the perception is going to be," Collins said. "Obviously I said that I wanted our coaches to come back. But at the end of the year, when we sat down and evaluated everything we thought that [we needed] for us to move forward, maybe some changes needed to be made."

Those changes did not include Hudgens, who is entering the second season of a two-year deal, or Warthen, who is well-liked amongst the pitching staff. With plate discipline a focus, the Mets raised their team on-base percentage from .314 in 2010 to .335 this season, ranking second in the National League. They also enjoyed an uptick in batting average and slugging, despite multiple significant injuries and the trade of Carlos Beltran.

Though the pitching staff actually saw its ERA jump from 3.70 to 4.19 in Warthen's third full season, Collins lauded the popular pitching coach's ability to lead a staff.

"He has a great relationship with our pitching staff," the manager said. "I watched him prepare on a daily basis and come up with a plan that -- when executed -- worked. There are nights obviously that the execution was not what we desired, and I saw some failures because of it. But I did think what Dan got out of most of our pitchers was very good, so I thought he deserved an opportunity to stay."

The Mets already have two of their four coaching replacements in place in Teufel, who managed Triple-A Buffalo last season, and Bones, who was Buffalo's pitching coach.

Though Double-A Binghamton manager Wally Backman is not a candidate to join the Major League staff, Alderson indicated that Backman is a strong candidate to take over Teufel's old job as Triple-A manager.

The rest of the big league staff will fall into place over the next few weeks.

"It's always hard, because I had relationships with these guys," Collins said. "But the thing that I thought was most important was the improvement of the ballclub and getting these players better and getting this team better, so we thought some changes had to be made."