The New England Patriots' biggest strength last season has somehow become the team's biggest weakness in 2020.
Even after losing four key defenders in free agency, two more to opt-outs and one in a trade, the Patriots' pass defense -- it's secondary, specifically -- was expected to be New England's constant in a season of turmoil.
That ... has not been the case.
The Patriots' defense ranks dead last in Football Outsiders' DVOA (defense-adjusted value over average) metric. Their run defense ranks 28th, and their pass defense ranks 31st. Only the New York Jets have been worse.
The Patriots' passing offense ranks 24th in DVOA, their rushing attack ranks third and their special teams rank seventh.
So, the Patriots' pass defense is unequivocally their biggest weakness, and the cause is complicated.
The Patriots, shockingly, rate second in the NFL in Pro Football Reference's pressure rate. They're first in hurry rate, 17th in knockdown rate and 28th in Football Outsiders' adjusted sack rate with just 13 sacks on the season.
So, the Patriots are getting after the quarterback at a high rate, which is usually a great sign, but they've been unable to finish. They've also allowed 212 rushing yards and two touchdowns to quarterbacks, so they're letting passers escape the pocket and pick up yards on the ground at a high rate.
Moving into the secondary, opposing quarterbacks are attempting a DADOT (average depth of target) of 9.5 yards against the Patriots. That's the second-highest average depth of target in the NFL. The Patriots have allowed 1,138 yards after catch, which accounts for 48.2 percent of the 2,361 passing yards the Patriots have allowed this season. That Patriots YAC rate (something we might have just made up) ranks 18th in the NFL.
The Patriots are being targeted deep but also are letting up a decent amount of yards after catch. That's not a great formula for success, and they're 15th in missed tackle rate with 59 missed tackles on 596 total plays.
The Patriots are allowing a league-worst 8 net yards per passing attempt, 12.6 yards per catch and 8.7 yards per attempt. They're sixth-worst in adjusted yards gained per pass attempt (which accounts for interceptions) and adjusted net yards per pass attempt (which accounts for interceptions and sacks). The Patriots rank fourth in interceptions with 11 this season, however.
If we told you heading into the season the Patriots' pass defense would be horrendous despite ranking second in pressure rate and fourth in interceptions, you would not believe us and would call us idiots.
The Patriots' pass defense is strange this season.
The Patriots' top cornerbacks, Stephon Gilmore (77 passer rating), JC Jackson (69.1 passer rating) and Jonathan Jones (94.1 passer rating), all have been solid in coverage though Gilmore missed three games with a knee injury.
Cornerback Jason McCourty (133.9 passer rating), safety Adrian Phillips (101.6 passer rating), linebacker Ja'Whaun Bentley (103.7 passer rating), strong safety Terrence Brooks (118.7 passer rating), safety Kyle Dugger (104.4 passer rating), free safety Devin McCourty (109.7 passer rating), linebacker Terez Hall (102.1 passer rating) and defensive back Joejuan Williams (135.4 passer rating) all have struggled to varying degrees.
And while Jackson leads the NFL with six interceptions and only has let up three touchdowns, he is also allowing 15.8 yards per completion and 9.2 yards per target.
While the Patriots' cornerback corps remains in place from previous seasons, New England does miss safeties Patrick Chung and Duron Harmon, linebackers Kyle Van Noy, Jamie Collins, Dont'a Hightower and Elandon Roberts and defensive tackle Danny Shelton.
Van Noy, Collins, Hightower and Shelton accounted for 22 of the Patriots' 47 sacks last season. The Patriots have lacked the communication and range Chung and Harmon provided at safety.
One of the strengths of last season's defense was their ability to work together as one collective unit and put Bill Belichick's complex vision in motion. The Patriots suddenly have new or inexperienced players like Chase Winovich, Byron Cowart, Bentley, Hall, Phillips and Dugger playing major roles this season and adjusting on the fly as New England adjusts its gameplan depending on the opposing team's offense. Communication and coverage breakdowns have followed. Pass rushers aren't containing correctly. Big plays have ensued.
If there's a glimmer of hope for the Patriots, it's that Gilmore's return should, in theory, strengthen the pass defense. New England also should be able to turn some of those pressures into sacks, causing negative plays and potential turnovers. The Patriots' interception rate should stay high as long as they keep generating pressure. Those young and inexperienced defenders should continue to develop, but it would be impossible to expect them to play as seamlessly as previous units. The Patriots simply lost too many pieces and didn't have starting-caliber players ready in reserve.
