It was also in St. Louis that beleaguered defensive coordinator Bob Babich made his NFL coaching debut, serving as a linebackers coach under Smith in 2003. Babich was the only coach to make the trek to Chicago with Smith, and his controversial promotion to defensive coordinator when Ron Rivera wasn't retained after a Super Bowl run is being blamed for the Bears' problems.

It's an essential truth of life in the NFL that maintaining success often comes down to how teams replace people as much as whom they originally hire.

Rams insiders point to Smith's departure as one of the turning points in Mike Martz's tenure as Rams coach. The team's defense declined after Smith left, the result of bad personnel decisions as much as bad coaching.

There is a microscope on Babich these days as a defense that keyed a Super Bowl run two years ago appears to be in a full-blown descent.

''It's a part of the job,'' Babich said of criticism this week that included a back-page story in the Sun-Times calling for his job. ''I have said many times, as the leader of this unit I am ultimately responsible for what goes on. It's part of the job. My focus right now is just doing everything we can to beat the Rams.''

Babich echoed comments made by Smith earlier this year when the head coach said he ''expects to be attacked'' when the team doesn't win. Smith said assistant coaches and players have the same expectation.

Smith, of course, is paid as an elite coach, and he knows it's on him to get his team to beat the struggling Rams, end a two-game slide and establish some confidence heading into a huge NFC North battle at Minnesota. Many fans and observers are accusing the organization of overvaluing its players and overpaying for the core of the defense. The same criticism will be put on Smith's $5 million-a-year contract if the team loses today.

Babich might be the man under scrutiny, but it's Smith who has to answer the questions of how he has replaced coaches who have left the organization. He has shown a willingness to make hard decisions when he believed change was needed.

Smith proved the point after his first season as a head coach when he fired offensive coordinator Terry Shea and offensive line coach Pete Hoener. It was far from a controversial move at the time because the offense struggled so mightily, but it nonetheless caught both men off-guard.

Shea said this week he figured the team's problems at quarterback -- they went through five that season -- would allow him another opportunity. Hoener was the only coach on the offensive staff with previous experience at his job and didn't feel he deserved to be fired.

Smith then hired Ron Turner, who was the Bears' coordinator from 1993 to '96, to replace Shea. Experience isn't essential for every job, but it can help.

In his book Outliers, author Malcolm Gladwell writes that researchers have settled on what they believe is the magic number for true expertise: 10,000 hours. In most jobs, that means five years of toil before one becomes a true master of the profession.

Nobody is ever going to get that kind of time in a league where the running joke is that NFL stands for Not For Long.

''I felt like I put in 10,000 hours in Chicago that year,'' Shea said. ''I know Lovie had a real definite plan in his mind when he was hired, and he was going to tap into the college ranks. He felt the college coaches brought a certain flair to their coaching style, and I think that was what Lovie was going to find. We probably came up a little bit short, obviously, in the experience factor of the NFL level, and I felt that was certainly evident on the offensive side of the ball.

''But that was Lovie's thought. He put a large premium on practice enthusiasm and attitude during the practice itself, and I think that is what he felt the college coaches brought to his practice culture.

''I would concur, but we came up short in terms of the NFL background.''

Smith and general manager Jerry Angelo, who helped put together Smith's staff, often have talked about the need for assistant coaches to teach and extolled the virtues of coaches coming out of the college ranks for their teaching ability.

Turner was hired out of Illinois, and his offensive line coach, Harry Hiestand, joined him. Turner was attracted to the autonomy of his position with the Bears and aspires to be a head coach in the NFL. With 10 head-coaching jobs expected to open at the end of the year, Turner was asked earlier this season who on his staff could take over the play-calling if he were to depart.

''A lot of them could,'' Turner said with a laugh.

He didn't name names. The word around the team when Rivera was not brought back was that Turner was the more valuable of the two coordinators because the Bears had someone in place to take over on defense, not on offense.

That man was thought to be Babich, but perhaps it is Smith himself. If the Bears can't get their act together on defense today, it might be time for the old defensive coordinator in Smith to make a re-appearance.

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Mike Mulligan and Sun-Times colleague Brian Hanley host a sports-talk show from 6 to 10 a.m. Monday through Friday on WSCR-AM (670).)