Hall of Fame coach Bill Walsh would always say that September was the month to play rookies to essentially define their roles and find out if they can eventually help the team win games in December. For Walsh, September was the time to learn -- about his team, about his chief opponents around the league -- and then make the right adjustments when it comes to players, coaches and schemes.
Likewise, we can learn something about all 32 teams now that September has come and gone. We learn which teams can make the adjustments, which ones can't, and which ones don't even know they need to. Three games into the season, there has actually been a great deal to learn about each team. Here's a breakdown of what we've learned:
That the Cards must cut down on their mental mistakes on defense. Most importantly, they must find the right system for quarterback Kevin Kolb to get rid of the ball in rhythm and feel confident in the pocket.
That they must improve their pass protection -- in part by getting better at right guard -- and get back to playing with the lead. Are they good enough on defense? I don't think so.
That Torrey Smith gives the Ravens speed on offense, something they need, and that the Ravens are still tough on defense. For the Ravens to be a Super Bowl team, they must continue to get big plays from Smith or Lee Evans.
That the Bills are the darlings of the league right now, but a bad defense in September is still a bad defense in December. The Bills will have to outscore everyone this year -- don't overreact to their 3-0 record.
That Cam Newton is for real, well ahead of his learning curve, and receiver Steve Smith is back. The defense has suffered some significant injuries and lacks depth. They might not be a playoff team, but will create problems for every opponent.
That the Bears offensive line is still not playoff quality, no matter what changes they made in the offseason. The Bears lack talent and quality depth. This is really hard to change at this point in the season.
That rookie quarterback Andy Dalton has been efficient but not always effective. The Bengals cannot convert third downs, cannot make big plays, and struggle to move the ball consistently. The Bengals are good on defense, but never get to play with the lead.
That the Brownies still lack playmakers on offense. They can't work the ball down the field (29th in the NFL in big plays) with their short passing game, and they will struggle on offense.
That the Broncos want to run the ball, but they can't. For all the talk about transitioning to a run team, the Broncos can't run. They don't have a runner, or an offensive line that can control the line of scrimmage. And that Tim Tebow does not have a role on the team -- short-term or long-term.
That the Packers have not missed a beat coming off their Super Bowl year. They are actually a better team than they were a year ago, especially on offense. It will take a team with a really good passing game to beat the Packers.
That the Texans are improved on defense and if they can solve their red-zone issues on offense and fourth-quarter collapses, then they can compete at the highest level. Can they make those adjustments? This is something we have not learned yet.
That the Jags just cannot throw the football. Only 40 completions this year, lowest in the NFL. The Jags are good enough on defense and can run the ball, but that formula worked in the '60s ... not now. The NFL is a throwing league and the Jags can't throw.
That the Chiefs have been crushed with injuries on both sides of the ball, but regardless, the Chiefs must significantly improve their talent level on offense. The Chiefs lack playmakers -- especially without Jamaal Charles.
That the Dolphins offensive line is a work in progress, their receivers drop too many balls and they can't score in the red zone. The Fins need a talent upgrade on both sides of the ball and understand that Reggie Bush is not a full-time back.
That the Vikings are a team with little skill on the outside on offense and the inability to make plays in the passing game -- in either half. They are not a playoff team and are in transition on both sides of the ball.
That the Pats can score at will, that Tom Brady is at times human and that their secondary must improve quickly. The Pats are a top team but are a work in progress on defense. Stevan Ridley looks like a big-time back.
That their offense is top notch, that tight end Jimmy Graham is the real deal and that their defense has huge holes. Their defense must gain some consistency and, like the Pats and Packers, must improve against the pass.
New York Giants
That their secondary is a mess, in part due to all the injuries they have suffered. The G-Men are one of those teams that could challenge late in the year when they get healthy. Their defensive front is for real and so is Jason Pierre-Paul.
New York Jets
That the Jets are still not able to get pressure on the passer without scheming with their blitz package. The Jets offensive line is in transition and their running game appears to not be the same as last year. Can that change? Not sure, because the Jets are not a team with great depth.
That the Raiders can run and pass this year on offense and will be in the race to win the AFC West all season. Their back seven on defense has to be a concern and if they can improve their play against the pass, they will create problems for every opponent.
That the dream is not a reality. The team has issues at linebacker, safety and in the offensive line. But most of all, quarterback Michael Vick is not playing near the same level he played last year. For the Eagles to meet high expectations, their defense must improve -- and so must Vick.
That opposing teams can handle the Steelers' blitz design and that LaMarr Woodley and James Harrison are not pressuring the passer the same as they did last year. For the Steelers to create turnovers, they must get more pressure on the passer and that starts with Harrison and Woodley.
That the Chargers can punt the ball effectively this year, but Philip Rivers is making more mistakes with the ball. The Chargers secondary is suspect right now and must improve -- especially Antoine Cason. Without Malcom Floyd or Antonio Gates, the Chargers offense is not as explosive.
That their defensive front seven is really strong and powerful. They are extremely tough against the run and play physical. But their offense is not effective throwing the ball and their offensive line struggles to consistently pass block.
That letting quarterback Matt Hasselbeck go was a mistake. And that Tarvaris Jackson is not the short- or long-term answer at quarterback. The Seahawks must improve their talent base to be a legitimate playoff contender, not just the best team in a really bad division.
That the Rams are not talented at wide receiver and cannot make plays on the outside, nor are they talented at corner, where they have a hard time preventing the ball from being thrown over their heads. The Rams have a great young quarterback in Sam Bradford but must get him some help.
That the Bucs have improved their defensive front rushing the passer, but they must find a way to improve their passing game. Right now, their ability to run the ball is not the same as a year ago -- which makes their ability to make big plays in the passing game more difficult.
That the Titans have a really good team, especially with Matt Hasselbeck leading the offense. They can throw the ball effectively, but they have struggled to run the ball -- which should improve as rookie coach Mike Munchak gets more involved in the run game, which he is doing this week.
That their defense is for real -- especially up front with their ability to rush the passer -- and they play the game with a physical style. Quarterback Rex Grossman can function well in this offense with their ability to run the ball.
Today my youngest son, Matthew, turns 21, and tomorrow my oldest son, Mick, turns 23. Happy birthday to you both -- I am really a proud papa.
Follow Michael Lombardi on Twitter @michaelombardi