Instead, they are 4-1 and coming off a dominating 48-3 performance over the Tampa Bay Buccaneers, who were 3-1 entering Sunday's contest. The only significant difference between last year's disaster and this year's surprise? New head coach Jim Harbaugh.

Part of it may be scheme. Part of it might be his attention to detail or his willingness to think outside the box, whether that be giving the players the day off on Mondays instead of Tuesdays, which is unprecedented, or staying in Youngstown, Ohio, for the week between the Bengals and Eagles games. A lot of it, however, is just belief.

There is a palpable difference in an NFL locker room between a team that believes in the head coach and the message he is delivering and one that doesn't. I know it all too well, unfortunately.

I played for five teams during my seven seasons and was coached by giants of the game like Bill Parcells, Bill Belichick, Joe Gibbs and Marty Schottenheimer. I was also coached by some who did not have a great command of the team, such as Dave Campo, Romeo Crennel and Steve Spurrier. The difference is like night and day.

In fairness to Campo, Crennel and Spurrier, it is always tougher for new coaches to establish credibility among the players than it is for guys who already have been there and done that. The other Hall of Fame-caliber coaches I mentioned all had a tremendous amount of success before I ever played for them.

But a team can begin to respect and eventually trust even a first-time NFL head coach if the players believe in his philosophy and the way he goes about his business. I know Mike Mularkey had us all believing with the Buffalo Bills in 2004, which was his rookie campaign as an NFL head coach.

When you talk with players and assistant coaches about Mike Singletary's tenure with the 49ers, very few of the stories you hear are good. From bullying the media to telling coordinator Jimmy Raye in front of the entire team that he had to change the offense, Singletary was ill-prepared to be an NFL head coach and the players knew it. Once the players know you aren't cut out for the big chair, you've got serious problems.

But the Niners have rectified those problems by getting the right coach. Similar to what Jim Schwartz has done with the Detroit Lions, Harbaugh has the players believing in what he is preaching.

Although players ultimately have to make the key plays to win games, the right coach can put them in position to make those plays and also to give them the faith that they can do it. Just ask San Francisco and Detroit.

From the inbox

Q. Before the season, the Raiders O-line was regarded as a major weakness, yet is now being hailed as a strength. What are the keys to a group like this coming together?

Stuart from Perth, Western Australia

A. That's a great question, because there are certain teams, such as Oakland and Buffalo, whose offensive lines are playing much better than I anticipated. They are both classic examples of the sum being better than the individual parts. I think coaching and continuity can certainly have a big impact on the performance of offensive lines. Also, sometimes individual players are just better than we realized. Finally, in Oakland's case especially, an elite talent like Raiders RB Darren McFadden can make spectacular plays that make the linemen look better than they really are. That's true to a lesser extent with Fred Jackson and Ryan Fitzpatrick in Buffalo.

Q. What exactly is a "hard" snap count? How do teams actually change the count? I mean, do they have specific words or numbers that they change from week to week?

Haseeb from Milwaukee

A. There are usually four to six counts available to an offense, and changing up that snap count is a valuable tool that the good offenses often take advantage of. Cadences include first sound, second sound, on "one," "two," "hard two," and silent cadence. The "hard" just tells the offense that the quarterback is really going to emphasize the first count in order to try to get the defense to jump offsides. It worked for the Bills on Sunday, helping them seal their win over the Philadelphia Eagles.

Q. I am on active duty in the Air Force so I have not had much time to watch as much football as I would like, but I have been waiting for the Texans to finally deliver and it looks like their year. But the Titans are right there. Could it be possible that we have TWO teams out of the AFC South in the playoffs? Furthermore what if the Colts were actually the Colts this year, would a possible 11-5 (Texans) team get snubbed from the playoffs as the Patriots did with Matt Cassel?

Stan from Houston

A. I think any team that goes 11-5 this year will make the postseason. That's especially true in the AFC South this year. Realistically, this is the Texans' best chance ever to win the division and a golden opportunity they'll probably never get again. Sunday's loss at home, even without Andre Johnson and against an emotional Raiders team following the death of Al Davis, was an especially bad one for a team that could have taken a lead over the surprising Titans. They need to win games like that if they are ever going to take the next step.

Ross Tucker, who played on the offensive line for five teams in a seven-year NFL career, writes regularly for ESPN.com.