Few slopes are more slippery than those occupied by your average college football powerhouse head coach. In a sport where national championship aspirations can evaporate in a single afternoon, coaches rarely feel comfortable for long. The high praise that accompanies a fast start to the season can disintegrate as fans – many of whom are alumni and/or donors and feel a greater sense of ownership in the program than fans of professional teams – turn on the man they had hailed only a few hours earlier.

A few of Saturday’s results illustrate the point clearly, most notably in East Lansing, Mich, where the 11th-ranked Michigan State Spartans fell in overtime to unranked Michigan, and in Tuscaloosa, Ala, where no. 5 Florida was shockingly routed by no. 15 Alabama.

Entering the day’s play, things were decidedly upside-down in Michigan. Not since the early 1970s had the Spartans been favored over their in-state rivals, who were reeling at 2-2. Michigan spent the week hearing about how its program was in a tailspin after four losses in its last six games. Much of the blame was heaped on head coach Lloyd Carr, who bore the indignity of seeing a “firelloydcarr.us” Web site pop up following a Week 4 loss to Wisconsin that had dropped the Wolverines out of the Top 25 after entering the season ranked fourth.

In 10-plus seasons at Michigan, Carr has won a national championship, five Big Ten titles, gone to three Rose Bowls and an Orange Bowl, and overseen a program that has generally avoided the taint of scandal. But many Michigan backers point to back-to-back Rose Bowl losses, six straight losses in road openers, and 1-3 records in recent years against both Notre Dame and Ohio State as evidence that it’s time for Carr to go.

Michigan State fans, meanwhile, spent the week hailing their coach, John L. Smith. His innovative spread offense had taken flight in his third season at the helm, pushing the Spartans to a 4-0 start and that lofty national ranking. Quarterback Drew Stanton was emerging as a dark-horse Heisman candidate. Suddenly, anything – including a Big Ten championship – seemed possible in a season that began with modest expectations. A win over Michigan was supposed to be a stepping-stone to the really big games against Ohio State and Penn State.

But a funny thing happened on the way to Smith’s coronation as the king of Michigan football: The Wolverines, buoyed by the return of star tailback Mike Hart, raced out to a 14-0 lead over the flat Spartans before ultimately winning 34-31 in overtime after Michigan State kicker John Goss missed two short kicks.

Smith, who could do wrong during the 4-0 start, came up with some curious calls that contributed to the loss – calls he’ll surely hear about should he tune into the local sportstalk radio stations this week. His strangely conservative approach in the red zone contributed to Michigan State’s failure to score an offensive touchdown after halftime. And with a chance to win the game in the final minute of regulation, Smith called a “hook and ladder” play, where the receiver catches the pass and immediately laterals to a trailing teammate in the hopes of breaking a long run. It’s a play that’s generally saved for desperate times – but Michigan had failed to stop Stanton’s passing all game, and two conventional plays might have put the Spartans in field goal range. Instead, the pass was stuffed and the game went to overtime.

In three hours, Smith had grown a set of goat horns and gone from innovative genius to the man who can’t beat Michigan (he’s 0-3 against the Wolverines). As for Carr, he’s probably quieted his critics, at least until Michigan tees it up next Saturday. Thankfully for him, he’s built up too much goodwill with the Michigan administration to worry about actually getting fired, but others have not been so lucky.

Florida coach Urban Meyer is also sure to have his “genius” label questioned this week. Like Smith, Meyer runs a complex spread-option offense. That Florida’s 4-0 start this season was due more to the play of its defense was largely ignored; in popular lore, it was the savior Meyer and his modern offense that was responsible for righting the Good Ship Gator.

But Meyer’s attack wilted against a suffocating Alabama defense, with early turnovers contributing to a 31-3 shellacking. Quarterback Chris Leak had a miserable day with just 16 completions in 37 attempts for 187 yards and two interceptions as Florida was held without a touchdown for the first time since 1992. Meyer can expect to face questions about whether his offense, honed in stints at mid-major conference schools Bowling Green and Utah, can stand up to an SEC-caliber defense.

In the meat grinder of a college season, sometimes winning is not enough to keep the critics at bay. Despite Alabama’s first 5-0 start since 1996, coach Mike Shula will spend some time this week explaining why his best offensive player, receiver Tyrone Prothro, was lost for the season trying to catch a fourth-down touchdown pass with a 28-point lead and nine minutes to play. Prothro, who broke his leg in a grisly injury reminiscent of Joe Theisman, set the tone for the win with an 87-yard touchdown reception on Alabama’s first play.

Despite the milestone win, Shula was forced to spend some time defending his decision to throw to his best receiver. Even after an important victory, the next call for a coach’s dismissal is never far away. Check the web -firemikeshula.com is up and running. As for Meyer, he’s a little safer -fireurbanmeyer.com exists, but it’s been put up preemptively in support of the Florida coach.

Nobody will feel sorry for these coaches anytime soon. They’re minor national celebrities, draw exorbitant salaries from public institutions, and it’s highly unlikely any of them has had to pay for a dinner tab in his hometown at any time in recent memory. Still, the pressure to succeed is immense, and job security is re-evaluated each Saturday.

Mr. Levine is a writer for FootballOutsiders.com.