ORCHARD PARK — In the wonderfully insightful Football Outsiders Almanac, founding editor Aaron Schatz writes that determining how the Buffalo Bills had such a strong pass defense last season “will go down as one of the great unanswered questions in recent human history.”

Anybody who astutely watched former coach Dick Jauron fulfill his fetish for drafting defensive backs could solve the mystery. Jauron had considerable sway on personnel decisions over the last four years, and during that time, 11 of the 34 players selected were defensive backs in college, notably first-round picks Donte Whitner and Leodis McKelvin.

Despite all that draft day investment, the Bills still found it necessary to give Terrence McGee a lucrative contract extension, acquire Drayton Florence and Bryan Scott in free agency, and convert George Wilson from receiver to safety. Curiously, on-the-rise corner Jabari Greer was allowed to sign with the Saints for less than what it cost to retain McGee. Understandably, Nate Clements was allowed to leave when it became apparent that he his market value far exceeded his actual worth.

Front-line players were added (and abandoned) based on how well they fit the coverage-oriented “Tampa 2” scheme, and, it seemed, for four years worth of gameplans, Jauron’s No. 1 priority was to prevent long completions.

All considered, it’s a wonder why the Bills didn’t have the NFL’s pass defense in ’09.

The Bills finished second in the NFL’s traditional pass defense ranking. The Outsiders’ complex DVOA metric ranked Buffalo third, behind Carolina and a Jets pass defense that was the fourth-most dominant unit in the 17 years of available data, trailing only two of the groups that defined the “Tampa 2” ethos, and the ’04 Bills that featured Clements, McGee, Troy Vincent, Lawyer Milloy, and a very good front seven.

The Bills’ biggest weakness last season was its pass rush. According to the Outsiders game-charting project, they ranked last in the league in quarterback hurry rate. When the Bills did put pressure on the quarterback, they were the most effective pass defense in football.

There was no flukiness to the Bills’ secondary success that would suggest a decline. They were consistent from week to week, on all three downs, against all different types of receivers. They were also impervious to injury. McKelvin, McGee, Whitner, Scott and rookie revelation Jairus Byrd combined to miss 32 games.

So what’s been the problem this preseason? After getting the better of a young receiving corps in camp, the Bills defensive backs came out flat at the opener in Washington. They rebounded a bit last week against an Indianapolis team that is notorious for playing poorly in exhibitions, then talked a lot of trash heading into Saturday’s matchup with Chad Ochocinco and Terrell Owens.

The dynamic divas were targeted seven times in the first half of the game, and produced five receptions for 58 yards. Ochocinco beat McKelvin to a lob pass in the end zone on play-action fake. McKelvin also got beat by T.O. for a first down, though he did come close to intercepting a long bomb intended for his former teammate.

The Bills had even more trouble defending Bengals tight end Jermaine Gresham, who, had he decided to leave Oklahoma after his junior season, could very well have been wearing a different color jersey Saturday. Gresham caught all four passes thrown his way, netting 45 yards and a touchdown, of which he later said, “they just didn’t cover me on that play.”

There were several reasons to think the Bills pass defense could be even better this year.

Remember, Byrd missed most of minicamps last spring because of Oregon’s late final exam schedule, then sat out training camp while recovering from sports hernia surgery. He went out and tied for the league lead with nine interceptions, despite playing through pain and learning a new position on the fly. What could he accomplish if with good health and a full offseason to prepare? We might not find out, since he’s currently sidelined indefinitely due to another surgery.

Optimists would also note that Whitner is moving back to his natural position as a run-supporting strong safety, McKelvin is maturing and possibly ready to live up to his pre-draft projections, McGee is (for now) not trying to play through pain, youngsters Reggie Corner and Ellis Lankster have playmaking ability (which we saw last night) and the new 3-4 defense has the potential to ignite the pass rush.

There’s been no signs so far of that last hope, but recent Outsiders research finds Maybin’s sack production in his redshirt sophomore season at Penn State and his vertical leap and short shuttle performance at the scouting combine are good indicators that he will develop into a capable edge rusher.

Buffalo’s defensive backs have the luxury of playing for the same position coach, George Catavolos, who guided them a year ago, but the new coordinator, George Edwards, is asking them to learn a few new tricks. Whitner in particular is raving about the chance to play more man-to-man and disguise coverages more than in the past. But clearly, the transition is a work in progress.

For all of Jauron’s faults, he and defensive lieutenant Perry Fewell put the secondary in position to succeed. Now that they’re gone, the pass defense is in the preliminary stages of a free fall.

Jauronimo!

The Football Outsiders Almanac 2010 can be purchased at FootballOutsiders.com. Contact reporter Jonah Bronstein at 282-2311, ext. 2258, or jonah.bronstein@niagara-gazette.com.