Trestman is out after going 13-19 in two seasons while Emery lasted just three years. The Bears went 5-11 in a mostly miserable season, never challenging for the NFC North lead after the first few weeks as quarterback Jay Cutler and the rest of the offence struggled mightily.
"This job was an opportunity of a lifetime. My only regret is that we didn't win enough games for that opportunity to continue," Emery said in a brief session with reporters.
He also thanked the organization and borrowed a lyric from singer Carrie Newcomer, saying, "We stand breathless on the clean edge of change. It's time to change and move forward."
Emery did not take questions from reporters.
Trestman, in a statement issued through the team, thanked the team-owning McCaskey family for the opportunity to coach the Bears.
"I also want to thank all the coaches and players who gave us everything we asked over the past two years," he said. "I have tremendous respect for this organization."
Trestman found he couldn't duplicate the success he enjoyed in the CFL with the Bears. Trestman was head coach of the Montreal Alouettes for five seasons before joining Chicago. He led the Alouettes to back-to-back Grey Cup titles in 2009 and 2010.
The new GM and coach could have a big decision to make with quarterback Jay Cutler. He tied Philip Rivers for the league lead with 18 interceptions after signing a huge, seven-year contract at the end of last season.
The house cleaning was certainly not what the Bears envisioned with a prolific offence returning intact and a rebuilt defence in tow. But little went right for Chicago this season.
There were distractions throughout the year, whether it was linebacker Lance Briggs being allowed to miss practice to open a restaurant in California the week of the opener or offensive co-ordinator Aaron Kromer admitting he was the NFL Network's source behind a critical report of Cutler late in the season.
Trestman, who was hired to get the most out of Cutler, benched the highly paid quarterback in favour of Jimmy Clausen for the second-to-last game of the season against Detroit. Cutler wound up starting the final game after Clausen suffered a concussion against the Lions, adding another chapter to a season-long soap opera.
Trestman also surprised some by allowing star receiver Brandon Marshall to fly to New York on a weekly basis to record Showtime's "Inside the NFL." Marshall, who is open about his struggles with borderline personality disorder, had an off year and at one point gave a rambling news conference over past allegations of domestic abuse. He also challenged a Detroit fan on Twitter to a boxing match for charity, and reporters standing in the hallway overheard him screaming in the locker room after a loss to Miami at Soldier Field in October that raised all sorts of questions about where the team was headed.
The answers came right after that.
The Bears joined the 1923 Rochester Jeffersons as the only teams to give up 50 or more points in back-to-back games while dropping the next two at New England and Green Bay. Trestman's meek response after defensive end Lamarr Houston suffered a season-ending knee injury celebrating a late sack against the Patriots — "I'm disappointed for Lamarr," he said twice — only fueled doubts about his leadership.
In recent weeks, it was clear changes were coming. The question was how far up the ladder they would go.
"At the end of the day, we didn't get the job done," tight end Martellus Bennett said. "It's not just coaches. It's everybody. We didn't have a successful year as players. So the coaches didn't have a successful year. I think everybody has their hand in the pot. And the gumbo doesn't taste that great when everybody's hand is in the pot."
Emery, who replaced the fired Jerry Angelo, was hired with a mandate to work with former coach Lovie Smith for at least one season. He fired Smith after the Bears missed the playoffs despite a 10-6 record in 2012, ending a nine-year run that produced three playoff appearances and a trip to the Super Bowl.
Since, then, the team has been in decline.
Trestman had never been a head coach in the NFL and at times seemed overmatched by the job. Along with the distractions, the offence took a huge step back: Chicago went from second in scoring to 23rd this year despite having all its starters back.
Giving Cutler a big contract after last season when the franchise player tag was an option is looking like another mistake. Emery did have success rebuilding the offensive line before the 2013 season, drafting Kyle Long and bringing in Jermon Bushrod and Matt Slauson.
But the makeover he gave the defence last off-season did not pay off. Chicago continued to rank among the league's worst in that area under Mel Tucker, with Jared Allen struggling and fellow newcomer Houston getting injured on that ill-advised sack celebration. Only the Saints and Falcons gave up more yards per game than the Bears.
Just like his predecessor, Emery also had a spotty draft record, with some hits such as Long and Alshon Jeffery and a big miss in Shea McClellin.
"Something has to change," veteran cornerback Tim Jennings said. "I'm not surprised by it. I mean, hopefully it will be a good one this time."
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