My duties on NFL Network constantly require me to comment on which teams are good and which are bad, who is playing well and who isn't, and -- most importantly -- who is going to win from one week to the next. Faced with these challenges, I'm annually reminded of Academy Award-winning screenwriter William Goldman Brian McCann Jersey ("Butch Ca sidy and the Sundance Kid," "The Prince s Bride") and his key rule to remember when trying to understand the way things work in Hollywood: "Nobody knows anything." At times, this is equally true in the NFL.Certainly, when you look at any given team and try to size up how good it is, and how it will fare in an upcoming game, you do so knowing that there are any number of factors that can totally alter your perspective (injuries, weather, matchups or just facing an opponent that, for whatever reason, suddenly plays out of its mind, at a level not previously seen). It's not a computer simulation -- it's real life, with 53 players on each side, and a lot of room for human error and inconsistency.For years, we've seen poorly coached, undisciplined teams show up big one week, then go mi sing in action the next week. What's different about the uneven performances this year is that we've seen some truly solid teams -- talented, mature clubs, led by some of the best coaches in the game -- showing the same irregular tendencies. Let's take a look at four notable examples:Pittsburgh Steelers (6-4)There isn't a more stable franchise in the NFL than the . Impeccable ownership, -winning coach, two-time champion quarterback, strong facilities and a roster of players who buy into the culture that has captured six Lombardi Trophies. Yet this team has been all over the map in terms of performance.How do you rush for 264 yards on 34 carries (7.8 per rush) in Week 3, then rush for just 85 yards on 27 carries (3.1 per) seven days later? The looked totally cluele s while -- who are better than they were last year, but still, without , not a team you expect to get trampled by -- then promptly scored , and over the next three weeks. During this stretch, finally adapted to 's system and played some of the best football of his career, posting back-to-back six-touchdown games against the and .Of course, just when you Houston Astros Jersey think the have it together, they turn around and . Even if you blame that lo s on , you still can't account for the ' jarring inconsistency.San Francisco 49ers (5-4)Entering this season, it was hard to find a more reliable contender than J.R. Richard Jersey the . They've appeared in three straight NFC Championship Games, playing stout defense, attacking opponents with a punishing running game and relying on the unique skill set of quarterback .In 2014, San Francisco is still fielding one of the most physically imposing defenses in the NFL, despite mi sing a number of key players like , and . So why has carried the ball 20-plus times in just two games ( and , two big wins)? Kaepernick's impact on the team is even harder to figure out. Over the past seven games, he is showing signs of maturity and consistency, completing 61 percent of his pa ses for 245 yards per game, with 10 touchdown throws to just two interceptions. Yet the are just 4-3 over those seven games.Cincinnati Bengals (5-3-1)In September, the looked like one of the most dominant teams in the NFL, particularly at home. They opened the season by and below 100 yards rushing. Then they stomped Tenne see, . After a bye week, though, Cincy's defense collapsed, giving up 107 points over the next three games -- sandwiched between blowout lo ses to conference rivals and .Through the first five games of the season, looked like he was taking the next step as a quarterback, completing 68.2 percent of his pa ses and posting a 98.4 QB rating. But over the last four games, both of those figures have plummeted (52.3 completion percentage, 54.4 QB rating) and Dalton's thrown two touchdown pa ses against six picks. Yes, has been banged up, but he was back in the Jungle last Thursday night, when Cincinnati looked '90s-era ghastly, rolling over in . Dalton had the sort of awful night that invites historical comparisons ("Was it as bad as Ryan Leaf's '98 start against Kansas City?"). And now you have to start wondering if this Cincinnati team -- coming off three straight playoff appearances -- has mi sed its window of opportunity.San Diego Chargers (5-4)Back in the preseason, people were saying this could be the best team in years. 's system was fully Yuli Gurriel Jersey implemented in San Diego, had re-established himself as an elite-level quarterback, was healthier than he'd been in ages and the defense was revitalized. All of that looked true during the ' five-game win streak. Then they were , and, at a time when you'd expect them to re-establish their credentials, played their worst game of the McCoy era in .Harrison: Power Rankings, Week 11In the latest edition of his weekly NFL pecking order, Elliot Harrison rewards a couple of notable road warriors. Have injuries hurt the ' offense? Certainly, but show me a team in the NFL in November that hasn't suffered key injuries. San Diego has a two-game respite and , but then they face what might be the toughest five-game closing stretch in the league: , and , and on the road and .ConclusionWhy are so many seemingly good teams -- with quality coaching and established quarterbacks -- falling on their faces? There are no simple answers. But I think it speaks to the parity in the league. The margin Carlos Beltran Jersey for error in the modern-day NFL is so slim that even a good team can look hopele s (see: ) and bad teams can rise up.Also, scouting and game-planning is at an all-time high. What works flawle sly in September can often be anticipated and stopped come October. For teams like the , , and , the time has come to readjust and recalibrate. The teams that do that succe sfully will still be playing in January.Follow Brian Billick on Twitter .