As happens in the offseason dead period, fans take to mock drafts, advanced stats, or anything that can get their hands on to occupy themselves until preseason starts. Kevin Skiver recently wrote an article analyzing Drees Brees' drop-off in performance when pressured in comparison to the average NFL quarterback based on ProFootballFocus metrics. I recently found another article (by PFF as well) that both aids Skiner's argument but also qualifies it and adds clarity.
Though I have above provided a link for you to access the article, I'll briefly cover the metrics to give better understanding. Quarterback "Pressure" is divided into four useful categories: "No Pressure without Blitz" (let's call this 1), "No Pressure with Blitz" (2), "Pressure without Blitz" (3), and "Pressure with Blitz" (4). Thus, PFF's Steve Palazzolo adds in a second Blitzing factor to allow for another layer of analysis. Further, the grades within these four categories were determined based on a wide range of factors including number of drop backs, scrambles, TDs, INTs, Time to Throw, Time to Pressure, YAC, Completion %, Accuracy %, TD %, INT %, QB rating, and many others. Now let's turn to the data to get a better picture of how Brees fairs to the rest of the league.
No Pressure, No Blitz (1) and Blitz (2)
Let's tackle the easiest one first -- Drew Brees is at the top of the charts when faced with no pressure with or without a blitz. Brees tallied a +27.9 rating only behind Peyton Manning's +33.5 when not faced with no blitz (1), and comes in with a +9.8 which is good for 5th when throwing against the blitz (2). It's apparent that Brees is much better than the average Quarterback when not facing pressure as the median grades for Quarterbacks with No Pressure, No Blitz and with Blitz is ~+3.4 and ~+3.6, respectively. I think we can decisively conclude that Brees is in the top-5 category and in that "Elite" category of Quarterbacks when not faced with pressure.
Pressure, No Blitz (3) and Blitz (4)
Now we turn to Brees when faced with pressure whether that is with or without Blitz. Looking at Pressure without Blitz (3), Kevin's data seems to be affirmed, in that not only does Brees have a poor -8.7 rating but he ranks in the bottom-10 quarterbacks (40th) in that regard. The data therefore affirms Brees in ranking less than the average quarterback in terms of pressure with no blitz (3). Now turning to Brees in Pressure against the Blitz (4), one realizes the value in the Blitz, No-Blitz distinction. While Brees rating is below average in terms of No-Blitz, he instead posts an impressive +1.7 rating which puts him 6th overall against blitz. Even more impressive, only 7 other Quarterbacks posted a positive rating at all. Brees then has a well-above average PFF rating when pressured and blitzed, but instead has a far below-average PFF rating when pressured and not blitzed.
First, it's important to understand that though the PFF QB ratings are objective in the sense that every Quarterback's rating is determined by the same formula using the same factors, what these ratings suggest to the reader are more subjective. In looking at the factors used, Brees' poor (3) rating was primarily due to below-average Yards per Attempt, Completion Percentage, Interception Percentage, and fairly average QB rating while being pressured without a blitz. These factors are mitigated however by a well-above average TD Percentage per Throw and Touchdown number (8).
Though I am limited to the statistics I have available, I have a couple speculative reasons for the data in regards to Pressure without Blitz (3) and with Blitz (4). First, I think the reason for the huge discrepancy between the Pressure with Blitz (4, +1.7) and the Pressure without Blitz (3, -8.7) ratings were because of Brees' high football IQ and ability to read defenses. At times when Brees was pressured using a Blitz, I believe Brees would be more likely to read the defense correctly and adapt before the play. Further, in game situations in which a Blitz is likely, an offensive play could be called which could counter accordingly (leaving available high-percentage passes when faced with pressure). I think these reasons could account for the high Pressure with Blitz rating (and substantially higher completion percentage [55.8% vs.44.2%] and Average yards per Attempt [8.4 vs. 4.1])
Second, I think the reason for such a low Pressure without Blitz rating (3, -8.7) was due to unexpected pressure and more frequent low-percentage passes (deep passes) when compared with the rest of the league. The first reason seems apparent- pressure without the blitz would conceivably catch Brees off guard more often. Indeed, the accumulated Quarterback ratings showed that Quarterbacks surprisingly faired worse (-151 vs. -132.9) on average against pressure without blitz than with pressure with blitz. The second reason might be due to a large number of deep passes, which would lead to Brees' high incompletion percentage and interception rate. When Pressured without Blitz, Brees threw 6 interceptions. In context, Brees threw 12 interceptions on the year. If Brees is throwing more low-percentage deep passes than the average quarterback in these times of duress then it would account for lower completion percentages and (possibly) more interceptions. Again, this seems somewhat justified in that Brees attempted 80 deep passes last year which is second to only Mathew Stafford. As the data shows, this is a high-risk high-reward style, which could account for Brees high TD number (8), INT number (6), and low completion-rate (44%). This high-risk high-reward style might lead to exaggerated stats in the times that are most statistically problematic for Quarterbacks -- Pressure with no blitz.
Thus, it seems to me that first Brees is only below average in comparison to the average NFL QB when pressured without the blitz. And second, the reason for this below average rating is both because of worse general performance for all quarterbacks during these times as well as Brees large percentage of deep passes in comparison with the rest of the league.