Welcome to Week 5 of the NFL regular season.

Our power panel -- a group of more than 80 writers, editors and TV personalities -- evaluated how teams are stacking up through four weeks and named a new No. 1 team for the second week in a row.

The updated rankings reflect that the Dallas Cowboys are surviving without Dak Prescott, who could return in Week 5, as they climb back up the list. It also reflects the Miami Dolphins' loss on Thursday night to the Cincinnati Bengals after quarterback Tua Tagovailoa (concussion) left the game on a stretcher. Tagovailoa already has been ruled out for Week 5. There are also 15 teams this week that have a 2-2 record.

Below, we checked in with NFL Nation reporters across the league and asked what the biggest issue faced by each team's defense is. From injuries to defending the run, every team has something it can improve on. We paired each response with the team's defensive efficiency rating and where that stacks up in the league. Defensive efficiency, powered by ESPN's Football Power Index, is rated on a 0-100 scale, based on the defense's contribution to scoring margin on per-play basis and adjusted for strength of opposing offenses faced.

So, let's get to it. Here's our new No. 1 team:

Jump to a team:
ARI | ATL | BAL | BUF | CAR | CHI | CIN
CLE | DAL | DEN | DET | GB | HOU | IND
JAX | KC | LV | LAC | LAR | MIA | MIN
NE | NO | NYG | NYJ | PHI | PIT | SF
SEA | TB | TEN | WSH

Week 4 ranking: 4

Defensive efficiency: 62.7
League rank: 9th

The biggest issue on defense is ... forcing turnovers.

The Chiefs have taken the ball from their opponent just four times. Only four teams have forced fewer turnovers, and all of them have losing records. The Chiefs are doing a nice job of pressuring the quarterback, so it figures the turnovers will come. In the meantime, the Chiefs have made the most of their four turnovers. They converted each into a touchdown. -- Adam Teicher

Week 4 ranking: 2

Defensive efficiency: 69.1
League rank: 5th

The biggest issue on defense is ... injuries.

The Bills' defense is ranked in the top five of almost every major category -- with third-down defense (41.3%, 19th) being one of a few concerns. But what has also stood out is how many injuries the Bills have accumulated, especially in the secondary. Cornerback Dane Jackson and safety Jordan Poyer have returned, but CB Christian Benford is still dealing with a right hand injury, S Micah Hyde (neck) is out for the season, DT Ed Oliver is recovering from a right ankle injury and CB Tre'Davious White continues to rehab a torn ACL in his left knee. -- Alaina Getzenberg

Week 4 ranking: 3

Defensive efficiency: 85.7
League rank: 1st

The biggest issue on defense is ... injuries to the secondary.

Even that's a reach, as corners Darius Slay (forearm) and Avonte Maddox (right ankle) are expected back soon. But there's little to pick apart. The Eagles are first in sacks (16), tied for first in takeaways (10), third in yards allowed (277.3 per game) and 10th in points allowed (17.8). They look really solid from front to back, even with safety Chauncey Gardner-Johnson, formerly of the New Orleans Saints, acclimating to a new position and team. -- Tim McManus

Week 4 ranking: 7

Defensive efficiency: 57.9
League rank: 13th

The biggest issue on defense is ... getting gouged on the ground, again.

Not only are the Packers allowing nearly 5 yards per rush, but they're having troubling bringing runners down. There are only three teams allowing more rushing yards after contact than the Packers. This was an issue last year, and it continues to be one this season. -- Rob Demovsky

Week 4 ranking: 1

Defensive efficiency: 46.2
League rank: 22nd

The biggest issue on defense is ... defending the pass.

Miami is currently the second-worst pass defense in the NFL through its first four games, although it hasn't translated to the scoreboard. The Dolphins have been stout against the run, and the numbers they've given up are a bit skewed considering Josh Allen's 63 pass attempts in Week 3 and Lamar Jackson's prolific first half in Week 2. Presumably, they'll return to form once Byron Jones returns from the physically unable to perform list -- which he's eligible to do this week. -- Marcel Louis-Jacques

Week 4 ranking: 5

Defensive efficiency: 58.2
League rank: 12th

The biggest issue on defense is ... injuries to the secondary.

The Rams have their best cornerback healthy (Jalen Ramsey) but have been dealing with several injuries in the secondary early in the season. The Rams were without cornerbacks Troy Hill (IR), David Long Jr. and Cobie Durant on Monday night against the 49ers, although they did get safety Jordan Fuller back. Los Angeles' defense, which ranked second in Football Outsiders' rush DVOA going into the Week 4 matchup, ranks significantly worse against the pass (23rd in the NFL). The Rams do have four interceptions this season. -- Sarah Barshop

Week 4 ranking: 9

Defensive efficiency: 39.6
League rank: 27th

The biggest issue on defense is ... soft coverage.

Vikings opponents are catching 75% of their targeted passes, the second-highest rate in the NFL. Of the 97 pass completions against them, 69 have come by receivers who have at least three yards of separation at the time of the throw, the fourth-highest total in the league. -- Kevin Seifert

Week 4 ranking: 8

Defensive efficiency: 76.1
League rank: 2nd

The biggest issue on defense is ... sluggish starts.

The Bucs have given up 27 total points in the first quarter through four weeks -- fourth most in the league -- yet their 68 total points given up would be fifth fewest. Players and coaches have talked about the need to communicate more from the get-go, and not just as the game progresses. It didn't help that they spotted the Chiefs 14 points with two lost fumbles in Week 4. -- Jenna Laine

Week 4 ranking: 6

Defensive efficiency: 52.3
League rank: 16th

The biggest issue on defense is ... finishing the game.

The Ravens have lost two games this season in which they have led by 17 points or more because they can't stop teams late in games. In the second half, Baltimore has given up an NFL-worst 1,019 yards while allowing 67 points. The Ravens used to get offenses off the field when they had Ray Lewis, Ed Reed and Terrell Suggs forcing clutch turnovers. This season, Baltimore defenders are making it too easy with missed assignments and no consistent pass rush. In the fourth quarter, opposing quarterbacks have posted an NFL-best 88.6 QBR against the Ravens, throwing five touchdowns and getting sacked twice. -- Jamison Hensley

Week 4 ranking: 10

Defensive efficiency: 68.2
League rank: 7th

The biggest issue on defense is ... the pass rush.

Honestly, there's very little to nitpick the Bengals' defense about. Cincinnati has one of the best defenses in the NFL. It ranks first in touchdowns allowed per drive and second in points allowed per drive. If there's one thing Cincinnati could improve, it's the pass rush. The Bengals are 26th in sacks per dropback, according to ESPN Stats & Information research, and are tied for 22nd in total sacks. But that could also be a function of how much teams are throwing against Cincinnati. Its defense has faced the third-most pass attempts in the NFL this season. -- Ben Baby

Week 4 ranking: 16

Defensive efficiency: 60.8
League rank: 10th

The biggest issue on defense is ... stopping the run.

This might be a minor quibble given how well the unit is playing as a whole. The Cowboys have not allowed 20 points in a game yet and have allowed just one touchdown in each game. But when the players say they still need to get better, slowing the run is their biggest must. They are allowing 5 yards per carry and have given up 20 runs of 10 yards or more in four games, including two runs of at least 33 yards in the past two games. With a team that runs the ball as effectively as the Eagles in their division, the Cowboys have to get better. -- Todd Archer

Week 4 ranking: 14

Defensive efficiency: 74.5
League rank: 3rd

The biggest issue on defense is ... the 49ers' offense.

The Niners' defense has been mostly dominant for the season's first month, but the win column doesn't reflect just how good it has been. San Francisco ranks near the top of the NFL in nearly every major defensive category, but the offense has been near the bottom of the league in a number of areas, most notably points scored. If the 49ers' defense can stay reasonably healthy, they don't need an offensive juggernaut to be a contender. But they do need much more than what they've gotten thus far. -- Nick Wagoner

Week 4 ranking: 15

Defensive efficiency: 51.0
League rank: 18th

The biggest issue on defense is ... injuries.

The Chargers' defense appeared dominant -- on paper -- entering the season. But injuries to key players have made it difficult for the unit to develop an identity through four games. Pro Bowl cornerback J.C. Jackson missed Weeks 1 and 3 after undergoing ankle surgery in August, and when he did give it a go in Week 2, he said he was playing at less than 100 percent. The Bolts are also having to adjust without Pro Bowl edge rusher Joey Bosa, who was placed on injured reserve after tearing his groin in Week 3. -- Lindsey Thiry

Week 4 ranking: 17

Defensive efficiency: 53.6
League rank: 15th

The biggest issue on defense is ... effectively rushing the passer.

The Giants have a top-10 pass defense at the moment. But they're going to have to rush the passer more effectively if that is going to continue. The Giants are 19th in the NFL with a pass rush win rate of 41.2%. They don't have an edge rusher with more than one sack and have called the third-most blitzes (57) so far this season. It might work against the quarterbacks they faced, but life is about to get much more difficult with Aaron Rodgers, Lamar Jackson, Trevor Lawrence and Geno Smith on deck. -- Jordan Raanan

Week 4 ranking: 13

Defensive efficiency: 68.3
League rank: 6th

The biggest issue on defense is ... the run defense.

The Jaguars had allowed just 55 yards per game on the ground through the first three games, but gave up 210 yards and four touchdowns rushing to the Eagles on Sunday. DT Folorunso Fatukasi had been a key part of the success, but he went down with a quad injury against the Eagles and his status going forward is unclear. The Jaguars have to figure out what went wrong because they face Dameon Pierce, Jonathan Taylor and Saquon Barkley the next three weeks. -- Michael DiRocco

Week 4 ranking: 18

Defensive efficiency: 47.3
League rank: 21st

The biggest issue on defense is ... allowing explosive plays.

Through four games, Tennessee has given up five plays of 40 yards or more. Four of them came through the air, which has sparked questions about the secondary. Outside of rookie Roger McCreary, all of the Titans' primary cornerbacks have been beat for explosive plays. The nickel package has struggled with veteran Terrance Mitchell and second-year player Caleb Farley finding their way as they rotate opposite of Kristian Fulton. Reinforcements could be on the way if Ugo Amadi recovers from an ankle injury that held him out of the past two games and Elijah Molden eventually returns from injured reserve. -- Turron Davenport

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Liz Loza gives Derrick Henry his props on his stellar performance in the Titans' victory over the Colts. (edited)

Week 4 ranking: 12

Defensive efficiency: 65.8
League rank: 8th

The biggest issue on defense is ... the nickel package.

The Broncos had surrendered only six points in the second half of their first three games combined, so they were rolling. However, in the Week 4 loss to the Raiders, the Broncos were pushed off the ball far too often in run defense. This was especially so when Denver was forced into its nickel package on defense and the Raiders then pounded away at it. They had a pile of big gains against the nickel, including a 43-yard run by Josh Jacobs in the third quarter. Jacobs finished with 144 yards rushing with two touchdowns as the Raiders rushed for 212 yards overall. This is something that needs to be corrected for Week 5. -- Jeff Legwold

Week 4 ranking: 11

Defensive efficiency: 39.5
League rank: 28

The biggest issue on defense is ... a banged-up defensive line.

Cleveland was missing three of its four starters along the defensive line in Sunday's loss to the Falcons, including star pass-rusher Myles Garrett. Coach Kevin Stefanski said Garrett could return next Sunday following last week's single-car crash. But Garrett is going to have to play through left shoulder and right biceps injuries, at least in the short term. DE Jadeveon Clowney has missed the past two games with an ankle injury. Without either, the Browns couldn't get pressure, while the Falcons ran the ball at will. With explosive offenses coming up, the D-line better healthy fast. -- Jake Trotter

Week 4 ranking: 19

Defensive efficiency: 51.0
League rank: 19th

The biggest issue on defense is ... getting home.

The Cardinals' four sacks are the fewest in the NFL, and their sacks per pass attempt rate is a league-low 2.88%. Losing Chandler Jones has taken a greater toll on Arizona's pass rush than expected. The Cardinals have been able to get to the quarterback and get their hands on him at times, as was the case against Kansas City's Patrick Mahomes, but getting opposing quarterbacks down has been a struggle. -- Josh Weinfuss

Week 4 ranking: 27

Defensive efficiency: 29.6
League rank: 31st

The biggest issue on defense is ... Jamal Adams' absence.

That's not to oversimplify what's gone wrong for Seattle's defense, which has had all sorts of issues during another awful start. The Seahawks are getting gashed against the run, in part because they're struggling in their transition to a 3-4 but also because they're missing tackles. They haven't gotten a consistent pass-rush from anyone other than linebacker Uchenna Nwosu. They're losing one-on-one matchups and committing too many penalties on the back end, where they're playing three young corners plus a backup at safety in Josh Adams because of the serious knee injury Adams suffered in the opener. A healthy Adams would be making a difference as a run defender and a pass-rusher. -- Brady Henderson

Week 4 ranking: 28

Defensive efficiency: 37.6
League rank: 29th

The biggest issue on defense is ... getting off the field on third down.

The Falcons are allowing opponents to convert 44% of third-down chances, ranking 24th out of the 32 teams. The defense has been much improved from a season ago, but this is the next step toward being the type of unit that defensive coordinator Dean Pees wants to have in Atlanta. -- Michael Rothstein

Week 4 ranking: 30

Defensive efficiency: 42.4
League rank: 25th

The biggest issue on defense is ... getting pass rush from someone other than Maxx Crosby.

Crosby has four of the Raiders' five sacks -- cornerback Nate Hobbs has the other -- and while that's a good early return on Las Vegas' four-year, $98.98 million investment via the extension Crosby got this offseason, the Raiders need more from the defensive line in general, Chandler Jones in particular. Jones has occupied double-teams and affected the passer, but for Crosby to remain effective, the Raiders would love for Jones, who signed a three-year, $51 million free-agent deal with Las Vegas this spring, to start getting home, too. -- Paul Gutierrez

Week 4 ranking: 31

Defensive efficiency: 42.7
League rank: 24th

The biggest issue on defense is ... third-down conversions.

The Jets have a 51% conversion rate on third down that ranks 31st out of 32 teams. Here's the weird part: It's not because of the pass rush. They're actually getting decent pressure on the quarterback, with a 35% pressure rate (19th) on third down. The problem is the coverage, specifically the safeties and linebackers. Cornerbacks D.J. Reed and rookie Sauce Gardner are holding up nicely on the outside, but they're giving up too many chunk plays in the middle of the field. Safety Lamarcus Joyner is coming off his best game (two interceptions), but the Jets need better coverage from S Jordan Whitehead and MLB C.J. Mosley. -- Rich Cimini

Week 4 ranking: 21

Defensive efficiency: 59.0
League rank: 11th

The biggest issue on defense is ... a consistent pass rush.

The Saints didn't have much of a pass rush to speak of to start the season, but they did get after Kirk Cousins on Sunday, finishing with three sacks. The Saints need Marcus Davenport and Cam Jordan to consistently step up, while getting production out of 2021 first-round pick Payton Turner, to have success moving forward. -- Katherine Terrell

Week 4 ranking: 25

Defensive efficiency: 21.8
League rank: 32nd

The biggest issue on defense is ... points allowed.

Detroit currently leads the league in scoring but also allows the most points in the league. The defense struggles in yards per rush, red zone efficiency and third-down conversions -- ranking last in all categories. Through four games this season, Detroit has allowed 141 points (35.3 points per game), which is the second most in franchise history -- trailing only the 0-16 squad from 2008. The Lions need to make some changes immediately, and head coach Dan Campbell knows it. -- Eric Woodyard

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Liza Loza highlights how Jared Goff's completion percentage continues to improve each week.

Week 4 ranking: 20

Defensive efficiency: 41.1
League rank: 26th

The biggest issue on defense is ... forcing takeaways.

The Colts' defense thrived on takeaways last season, producing 33 turnovers. But the unit ranks among the worst in the league this season in this regard, forcing just three turnovers through four games. A big reason for this is the absence of linebacker Shaquille Leonard, who made his short-lived season debut on Sunday, only to leave with a concussion in the second half. Leonard has been ruled out for Thursday night's game at Denver. -- Stephen Holder

Week 4 ranking: 23

Defensive efficiency: 46.0
League rank: 23rd

The biggest issue on defense is ... defending the run.

After Baltimore totaled 126 yards in the second half in Week 3, and Green Bay totaled 199 yards on 35 carries overall in Week 4, it has exposed a vulnerability for the Patriots. Losing sturdy DT Lawrence Guy to a shoulder injury is a contributing factor, but that alone doesn't fully explain an alarming past six quarters the defense has played against the run. The linebacker play has struggled too, leading to veteran Jamie Collins' return to the team on Monday. -- Mike Reiss

Week 4 ranking: 22

Defensive efficiency: 51.9
League rank: 17th

The biggest issue on defense is ... run defense.

The Bears are the NFL's worst team against the run, having allowed 733 rushing yards through four games (183.3 yards per game), and are on pace to reach historically low marks. As if getting gashed by Aaron Jones and AJ Dillon wasn't enough to have the Bears licking their wounds after a Week 2 loss at Green Bay, Giants running back Saquon Barkley totaled 145 yards on 31 carries and earned 94 of his rushing yards after first contact in Week 4. -- Courtney Cronin

Week 4 ranking: 24

Defensive efficiency: 54.3
League rank: 14th

The biggest issue on defense is ... no T.J. Watt.

After dropping three straight, there are plenty of issues to point to on the defensive side, but the root of it stems from Watt's absence. Since the reigning NFL Defensive Player of the Year tore his pectoral at the end of regulation in Week 1, the Steelers have given up an average of 23 points per game and recorded just three total sacks. Watt is the cog in the defense that makes everything go, and without a formidable pass rush, the rest of the defense isn't succeeding in picking up the slack. -- Brooke Pryor

Week 4 ranking: 26

Defensive efficiency: 36.3
League rank: 30

The biggest issue on defense is ... allowing big plays.

Washington has surrendered an NFL-best 12 plays of 30 yards or more -- 10 of those have been pass plays -- often because of blown coverages. Dallas' struggling offense managed three pass plays of at least that length. On the Cowboys' opening drive, one pass went for 31 yards while the other five plays managed a combined 9 yards. Sometimes inexperience has led to the big plays, but other times it's just corners getting beat, whether outright or because they anticipated help that didn't arrive. The concerning part for Washington is that it lacks corner depth and its starters are both established vets -- Kendall Fuller and William Jackson III. -- John Keim

Week 4 ranking: 29

Defensive efficiency: 69.3
League rank: 4th

The biggest issue on defense is ... the fourth quarter.

The Panthers are allowing 10.5 points a game in the final quarter to rank among the worst in the league. That's been costly for a team that continues to lose close games, and fatigue might be a problem. The offense has been so bad with three-and-outs and turnovers that the defense continues to be forced back on the field. Sunday's 26-16 loss to Arizona was a prime example as the Cardinals had the ball for just over 38 minutes to 21:25 for Carolina. -- David Newton

Week 4 ranking: 32

Defensive efficiency: 47.6
League rank: 20th

The biggest issue on defense is ... defending the run.

The Texans are allowing 5.1 yards per carry and have allowed 688 total rushing yards, the second most in the NFL. They've allowed 34 first downs on the ground, the third most in the NFL. It's one of the many reasons they're winless, and it has made them vulnerable in the play-action game, too. They've allowed 415 yards off play-action, which is the fourth most in the NFL. -- DJ Bien-Aime