A well educated Saints fan recently tried to convince me that the Saints' front office personnel were poor evaluators of talent. He made several compelling points, including that the team missed completely on the 2007 draft and free agency. And he was right -- they certainly didn't derive any value from their draft or their large-money acquisitions (cough, Jason David) this year. He admitted that the Saints had a remarkable string of luck in 2006. Nevertheless, the fan believed David so underperformed his contract the Saints should release him as soon as possible.

He was probably right.

It reminded me of an article I meant to discuss more, the Football Outsiders' revelation of the Best and Worse defensive backs (T/Y, SouthernSaint). David fared poorly, ranking as the worst corner in terms of both Success Rate and yards per pass. David's 32 percent success rate was followed by Detroit's Stanley Wilson (36) and Cincinnati's young tandem of Jonathan Joseph (39) and Leon Hall (36). David allowed a league-worst 14.5 yards per pass, which was actually more than a hole in the zone (11.9). Of David's performance, Aaron Schatz said:

Yes, Jason David is worse than throwing at a hole in the zone. Fred Thomas gave up 9.3 yards per pass last year. Egads. I guess not every player is meant to play in every defensive scheme. He still has ridiculously bad numbers that make you wonder why anyone would ever throw to a receiver covered by Mike McKenzie.

In late December, FO game-charter  Nick Walters noted the entire pass defense was rotten for much of the season.

The question of exactly how bad the New Orleans pass defense is can be answered fairly decisively: It’s the worst in the league. The only passing defense stat that goes the Saints way is covering No. 2 receivers, where they are ranked 10th. Otherwise, the Saints are worst in the league against No. 1 receivers and among the worst against tight ends, running backs, and other receivers. To be sure, last year’s pass defense wasn’t good either, but it was nowhere near the worst in the league.

In the Colts’ Tampa-2, Jason David’s deficiencies were somewhat hidden; corners almost always have safety help in that scheme. The Saints, though, like to play a Cover-1 man defense. As it turns out, that’s probably the worst possible scheme for David, as it means his every mistake is amplified. Every time he bites on a pump fake, it’s another long rundown for Harper as David trails vainly in the distance. Opposing offenses salivate at lining up their go-to receiver one-on-one with the Saints’ right corner. It just doesn’t look like the team’s going to make a change this season, though, meaning a probably limited lifespan for the Saints as a potential playoff team.

Walters found that Mike McKenzie, Roman Harper and Jason Craft graded out well. Usama Young struggled:

It doesn’t look like Harper’s the problem. There aren’t yet enough numbers from which to draw meaningful conclusions, though the ones we have are all positive — his Success Rate was 62 percent last season and 50 percent so far this year, and his yards per pass are 5.2 (2006) and 8.4 (2007). He was clearly a better option than Stoutmire last year before going down, and has been reasonably good this year.
It’s the same story with the other corner, Mike McKenzie.

There’s also Jason Craft, the nickel corner, who actually has more targets than David this year and has produced better numbers (53 percent, 6.4 yards per pass). One player who’s clearly not ready, though, is rookie Usama Young. He has poor horrible numbers in limited playing time and makes numerous errors in run defense.

FO actually rated McKenzie the fourth-best corner in the league ranked by success rate (64 percent, double David's) and seventh best in yards per attempt (5.5). Walters wrote that:

On some series — such as early against Carolina in Week 12 — the differences between McKenzie and David in both pass coverage and simple tackling were starkly contrasted. McKenzie’s coverage is usually tight, while David is usually chasing; McKenzie is also usually actually watching his man, whereas David likes to watch the quarterback.

For the record, McKenzie, David and Harper tied in interceptions with three. David and Harper tied several other players in forcing two fumbles.