While team performance often drives personnel decisions, canning a coach can serve as more of a public relations action than a football move, said Andrew Zimbalist, a professor of economics at Smith College who has written extensively on sports. He noted that letting go of coaches can "send a message to the fan base" after a string of losing seasons.
"You want to give fans the sense that you'll turn the corner now," Zimbalist said.
Head coach salaries are "not irrelevant, but just a small factor" in actual hiring decisions, Zimbalist said. As the average franchise accumulates about $300 million in annual revenue, paying a coach $7 million rather than $4 million will rarely affect the process, he said.
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Franchises' relationships with fans and media can prove vital during transition periods, said John Challenger, CEO of job placement firm Challenger, Gray & Christmas. Teams, like businesses, often act quickly to expedite a "seamless" transition and show they're well-run organizations, he said.
"Like businesses, you have a vacuum at the top," Challenger said. "These teams are kind of directionless."
He added that similar to companies letting go of a CEO, teams firing a head coach or general manager might not eliminate all their problems. Incompetence at lower levels of the organization can persist through a change in top leadership—just as it can in corporate America.
Challenger noted that the Bears ditched both Trestman and general manager Phil Emery but have thus far kept quarterback Jay Cutler, who threw a league-high 18 interceptions while making a whopping $17.5 million.