Last week on NFL Network's "Playbook," Sterling Sharpe asked me what the first-time head coaches were thinking heading into their regular-season debuts. I answered by referencing former Secretary of Defense Donald Rumsfeld's famous 2002 press conference in which he explored the concept of the "known knowns" and their variants: "There are things we know we know," Rumsfeld said. "We also know there are known unknowns; that is to say we know there are some things we do not know. But there are also unknown unknowns -- the ones we don't know we don't know."
I can't think of a better explanation for what it's like to be a first-time head coach in the NFL. You spend a professional lifetime preparing for this day, thinking through every possible contingency that you might encounter, and drawing on every experience you've had. You imagine this perfect theoretical future where you can calmly implement these plans, and sagely avoid the typical pitfalls of rookie coaches. Then, when you step into the job, and the relentless, immersive experience of being an NFL head coach begins, you quickly realize just how unprepared you really are. (I remember, for me, the "unknown unknown" was the sudden realization that I would need to get used to the idea that when I suggested something, there was now someone who actually would run out and try to do it; that was an adjustment.)
With the "known knowns" concept in mind, here's a look at the quartet of first-time NFL head coaches after their initial Sunday on the job:
Mike Pettine, Cleveland Browns (0-1)
Known Known: Pettine knows he inherited a team, and a city, that has not won a playoff game since Jan. 1, 1995 -- and that he is the ninth head coach to lead the franchise since that date. And heading into Sunday's opener in Pittsburgh, Pettine also knew that Ben Roethlisberger was 17-1 against his new team.
Known Unknown: With prior experience in the AFC North -- Pettine was a member of my staff in Baltimore -- he knew how tough an opponent the Steelers could be. He didn't know how his team would respond to the likely adversity, and in that respect, he saw some encouraging signs on Sunday. After heading into halftime down 27-3, the Browns fought back to tie the score in the fourth quarter, before eventually losing, 30-27.
Unknown Unknown: Pettine now has a better sense of the media circus that accompanies Johnny Manziel, but what he can't calculate is how that is going to play out in the regular season. Pettine also cannot be sure when the right time might be to start his very young -- and, let's face it, very immature -- future franchise quarterback. The veteran, Brian Hoyer, was solid in bringing the team back Sunday, flashing some of the same promise he demonstrated while leading the Browns to a pair of wins last September. But with the next two games against New Orleans and division rival Baltimore, Pettine can't know how the Browns will adapt to a tough early schedule, how soon fans and media will begin agitating for a change at QB, and how that nearly-inevitable development will affect the team.
Jay Gruden, Washington Redskins (0-1)
Known Known: Gruden knows he was hired to do one thing: turn third-year quarterback Robert Griffin III into the franchise quarterback he was drafted to be -- and, in all fairness, appeared to be during his rookie season in 2012.
Known Unknown: Gruden knows the transition into a new style of play demands that RGIII rely on his ability to produce primarily from the pocket, as opposed to running around and exposing himself to injury. What Gruden doesn't know is how long a process this will be, and if the team can win games while its quarterback is still making the transition.
Unknown Unknown: RGIII was a respectable 29-of-37 passing for 267 yards on Sunday -- and even more notably, logged just three rushes for two yards. If you'd shown Gruden his quarterback's eventual stat line before the game, he likely would have been pleased. What he couldn't have known was how abysmal the offense would look as a whole, generating just a single score on a four-play, 46-yard drive. The 17-6 loss underscored a simple truth: The quarterback's job isn't merely to complete passes. It's also to lead the team, to hold teammates accountable, to will the offense into performing as a cohesive unit. In the past, when his team has been stagnant, RGIII has often taken things into his own hands, scrambling to make a big play. Is Griffin capable of lifting his team without exposing himself to the injury risks that he encountered while running the ball an average of 103 times per season in his first two NFL campaigns?
Mike Zimmer, Minnesota Vikings (1-0)
Known Known: Zimmer knows he took over a franchise with some key ingredients already in place -- the Vikings might be this year's model of a team that runs the ball well, plays good defense and relies on a game manager who doesn't commit turnovers at quarterback. (Last year's edition: Andy Reid's 11-5 Kansas City Chiefs.) Adrian Peterson is arguably still the best running back in the NFL, Zimmer has worked wonders with defenses in the past (and would seem to have the raw materials to do so again), and Matt Cassel is pretty much the prototypical low-risk/low-upside, game-managing QB.
Known Unknown: In a division with Aaron Rodgers, Matthew Stafford and Jay Cutler, Zimmer surely realizes that Minnesota must score points to seriously compete for the NFC North title. What he doesn't know is if Cassel -- or first-round pick Teddy Bridgewater -- can be good enough to take the Vikings' offense to the next level. Though the first Sunday, a 34-6 drubbing of the Rams in St. Louis, was obviously as good a start as Zimmer could've hoped for.
Unknown Unknown: The continued maturation of wideout Cordarrelle Patterson, who showcased his explosive playmaking abilities on Sunday, is a good sign for whoever the long-term quarterback winds up being. But when to push Cassel aside and start giving Bridgewater his shot is something that can't really be known until the Vikes get through this brutal stretch in their upcoming schedule: vs. Patriots, at Saints, vs. Falcons, at Packers. How the offense evolves in the coming years -- as the Vikings spend two seasons playing in an outdoor stadium before moving back indoors in 2016 -- is yet another unknown at this point.
Bill O'Brien, Houston Texans (1-0)
Known Known: O'Brien might have been better equipped than most for his first experience as an NFL head coach, having been a head man in the college ranks at Penn State (especially given all the turmoil facing the university when he took over). When he accepted the Texans job, O'Brien knew he inherited a top-flight defense, headlined by the most dominant defensive lineman in the game (J.J. Watt).
Known Unknown: The Seahawks' Super Bowl triumph last season highlighted a formula for success that O'Brien will relate with: A team can win it all with a good running attack, great defense and a quarterback who does not bury the team with turnovers. What O'Brien doesn't know is if anyone among a cast of quarterbacks led by Ryan Fitzpatrick can step up and give the team relatively modest production (20 or so touchdown passes and less than 10 interceptions). Fitzpatrick gave his coach that kind of performance in the win against Washington on Sunday (206 passing yards, one touchdown and zero turnovers), but can he do that on a weekly basis?
Unknown Unknown: Very late in the preseason, O'Brien acquired quarterback Ryan Mallett from the New England Patriots. This broadened Houston's options at QB -- Fitzpatrick is getting the first shot, while Mallett and fourth-round pick Tom Savage are dueling to be the next man up. One of the issues O'Brien can't foresee yet is one that other coaches (including myself, in Baltimore) have encountered in the past: What if your defense is strong enough to keep you competitive -- at around .500 or better -- but none of your quarterbacks really emerge to push you beyond that? When that happens, it becomes really difficult to find the franchise quarterback. None of the guys you have are good enough to take you to the next level, but you're never bad enough to get a shot at an Andrew Luck or Matt Ryan in the top portion of the first round. It's a conundrum that has frustrated coaches and general managers alike for decades.
Follow Brian Billick on Twitter @coachbillick.