Each team has eight games against the NFC West and AFC South, divisions that are in quarterback transition. The only elite quarterback is Houston's Matt Schaub. Those divisions have four rookie or second-year quarterbacks. The Arizona Cardinals have John Skelton, who is inexperienced.
Considering the Packers' and Patriots' problems on defense last season, these games offer them the chance to gain some confidence and improve. The Packers have the toughest task Sunday -- they host the San Francisco 49ers, the favorites to win the NFC West. The Patriots travel to Nashville to play the Tennessee Titans and Jake Locker, who is making his first start.
Here are the top 10 trends heading into the first week of the season:
1. Impact of replacement officials: After failing to get a deal with the current officials, the NFL will use the replacement officials who struggled on the field during the preseason. Surprisingly, the replacements called more penalties than the established officials did in the 2011 preseason. Will that trend carry into the regular season? If they don't call a lot of penalties, teams such as the Seahawks, Eagles and others who use man-to-man press with their cornerbacks could have an advantage in jamming receivers without fear of flags. Two other games to watch will be Atlanta-Kansas City and Baltimore-Cincinnati. Matt Ryan of the Falcons and Joe Flacco of the Ravens are using more no-huddle, but those offenses could be slowed down if the officials take too much time spotting the football correctly. In the preseason, trouble spotting the ball created delays of more than 30 seconds.
Despite the problems in the preseason, NFL commissioner Roger Goodell was pleased with the job the replacement referees did in Wednesday night's Cowboys-Giants game.
2. Holes in the offensive line: A few teams could have trouble running the football up the middle because of injuries. The Bengals lost center Kyle Cook and guard Travelle Wharton. Center Jeff Faine was signed off the street to start and could have trouble against the Ravens' 3-4 defense. In his best days, Faine struggled against 3-4 nose tackles. The Tampa Bay Buccaneers lost their best interior blocker -- guard Davin Joseph -- for the season. First-year coach Greg Schiano may have trouble running the ball against the Carolina Panthers. The Steelers, who open in Denver, have to fill in for the loss of first-round pick David DeCastro, a right guard.
3. Defending the young quarterbacks: Five rookie quarterbacks will be getting their first starts. The surprise of the group is third-round choice Russell Wilson of the Seahawks. Wilson, who is 5-foot-11, beat out Matt Flynn with his strong arm and tireless work ethic. He faces an Arizona Cardinals 3-4 defense that will try to keep him in the pocket and limit his vision in throwing to receivers in the middle of the field. Andrew Luck's debut for the Indianapolis Colts is against the Chicago Bears' Cover 2 defense. Robert Griffin III faces the New Orleans Saints' defense in the Superdome. Ryan Tannehill of the Dolphins draws Wade Phillips' tough Houston Texans defense on the road. Brandon Weeden of the Cleveland Browns is the only rookie quarterback who gets a home game. He faces the Philadelphia Eagles, who have gone more to man-to-man coverage. That will make it tough for Weeden's young receivers to get separation.
4. Peyton Manning's debut: The Steelers lost a playoff game against Tim Tebow and the Broncos last year in Denver because the middle of the field was left wide open for a Demaryius Thomas touchdown reception. Part of the problem was that a backup safety did not cover for the blitzing Troy Polamalu. Normally, safety Ryan Clark covers that void, but he's not going to play Sunday because of health concerns related to playing in the mile-high altitude. On Sunday night, the Steelers will be facing Peyton Manning, one of the smartest quarterbacks of his era. Steelers defensive coordinator Dick LeBeau will be testing Manning with blitzes, but Manning could come up with big plays if the Steelers guess wrong.
5. Fantasy or reality: In a normal year, a Jacksonville Jaguars opening game against the Minnesota Vikings would be a fantasy football dream because of Adrian Peterson and Maurice Jones-Drew. Not this year. Neither knows how much or how well he will play. Peterson is coming off a knee reconstruction. Jones-Drew ended a 38-day holdout over the weekend and isn't going to start. Instead, the Jaguars are going to use him as their third-down back. In a game like this, normally you'd expect Peterson and Jones-Drew to have at least 20 carries each. In this opener, they might not have 20 carries combined.
6. Return of other running backs with injured knees: Several running backs are coming back from major knee surgeries. Among them are Ryan Williams and Beanie Wells of the Arizona Cardinals, who face the Seattle Seahawks in the opening game. Jamaal Charles is making a return after suffering a season-ending ACL tear in Week 2, as he and the Chiefs face the Falcons. Knowshon Moreno has returned after surgery to his ACL and is now a backup to Willis McGahee in Denver. The Broncos' opponents, the Steelers, have to fill the void left by Rashard Mendenhall. The running back's return from surgery to repair a torn ACL could keep him on the inactive list for the first few weeks of the season.
7. A divisional game with plenty of gimmicks: The Buffalo Bills open against the New York Jets, and it could be one of the most interesting chess matches on Sunday. Bills coach Chan Gailey spreads the field with four and five wide receivers and forces 3-4 defensive teams into sub-packages. Rex Ryan prefers a base 3-4, but the Jets will be in four-man defensive line sub-packages most of the day. Also on Sunday, everyone will find out how the Jets will use backup quarterback Tim Tebow. Offensive coordinator Tony Sparano will unveil the type of Wildcat packages he has designed for Tebow to go along with the packages showing how Tebow will be used in the red zone. What remains to be seen is how these plays will affect starting quarterback Mark Sanchez.
9. More backfield questions: The Washington Redskins and Detroit Lions open the season with uncertainty in the backfield. The Lions are starting Kevin Smith after failing to trade for a running back at the cutdown deadline. Mikel Leshoure is suspended for the first two games, and Jahvid Best went on the PUP list because of concussion problems. The Lions open against the St. Louis Rams, who have 31 new players on Jeff Fisher's roster. Mike Shanahan hoped Tim Hightower would emerge as the Redskins' starting back, but Hightower was cut. Instead, the Redskins open against the Saints with a three-headed backfield: Alfred Morris, Evan Royster and Roy Helu.
10. The interim season: No team had a worse offseason than the Saints. They lost two coaches, a general manager and two players to suspension because of the pay-for-hit bounty allegations. If that weren't bad enough, the Saints had to vacate New Orleans last week because of Hurricane Isaac. On Sunday, the focus returns to football. Aaron Kromer takes over for Sean Peyton and Joe Vitt as the interim coach. An arbitration panel on Friday ruled for the players, clearing the way for them to start Sunday against the Redskins.