Does Speed Kill?…Defense Edition
After looking into how offensive speed impacts yardage production a few days ago — and finding out that speed barely moved the needle on yardage — I started wondering about the other side of the ball. Offense is about creating separation and finding lanes, etc, but speed is just as important on the other side of the ball: closing on the ball carrier, getting from the snap to the quarterback, running stride for stride with a burner WR. If speed was ever going to show up in the numbers, defense felt like the place to look. So I pulled the same average roster speed metric and lined it up against total yards allowed per game to see if the speed kills theory holds up any better on defense.
Short answer: Maybe a little.
The Fast Defenses
The Cowboys have the fastest defense in the league by team average, and unlike most of the speed demons from the offensive piece, they actually back it up — 2nd in the NFL in total yards allowed. The Lions, 6th in defensive speed, sit 3rd in yards allowed. The Chiefs, 8th in speed, are 5th in yards allowed. That's three of the top eight fastest defenses also parked inside the top five in yards allowed, which is a much tighter cluster than anything I saw on offense.
It's not a complete correlation, though. Those poorly-run Dolphins are the 2nd-fastest defense in the league and finished a pedestrian 17th in yards allowed. The Giants, 9th in speed, were 28th in yards allowed — one of the widest gaps on the board.
Here are the Top 10 Fastest Defenses and their Yards Allowed Ranking
Team Avg Speed Rank Yards Allowed Rank
Cowboys 1 2
Dolphins 2 17
Eagles 3 19
Chargers 4 18
Broncos 5 25
Lions 6 3
Packers 7 14
Chiefs 8 5
Giants 9 28
Ravens 10 16
The Slow Defenses
Here's where the offense comparisons really break down. On offense, the slowest teams in the league — Broncos, Rams, Cowboys — were some of the best yardage offenses around. On defense, the bottom of the speed rankings is mostly just bad. The Cardinals, dead last in defensive speed, finished 20th in yards allowed. The Browns, 31st in speed, were 27th in yards allowed. The Vikings, 28th in speed, were 30th in yards allowed — one of only a handful of teams that were bad at both.
There's one loud exception, and it's a big one: the Falcons. Slowest-ranked defense in the top ten of the "slow" group at 23rd, yet somehow the number one yards-allowed defense in the entire league. If any team wants to be the Broncos/Cowboys of this article — proof that scheme and discipline can outrun actual speed — it's Atlanta.
Here are the Top 10 Slowest Defenses and their Yards Allowed Ranking
Team Avg Speed Rank Yards Allowed Rank
Falcons 23 1
Bears 24 22
Patriots 25 9
Raiders 26 21
Redskins 27 10
Vikings 28 30
Texans 29 13
Buccaneers 30 24
Browns 31 27
Cardinals 32 20
So Does Speed Actually Help On Defense?
Running the numbers across all 32 teams, there appears to be a slight relationship between defensive speed rank and yards-allowed rank — nowhere near a strong correlation, but noticeably more of one than offense showed. Roughly speaking, if you sorted every team from fastest to slowest defense, you'd see a mild but real drift toward worse yardage numbers as you got slower. It's not a rule. It's a lean.
The same data caveat from the offense article still applies here, maybe even more so. This speed number is still just whoever is starting at each position on the most recent depth chart — no injuries, no rotational speed off the bench, no nickel/dime packages factored in. That may matter even more on defense, where situational subs (a speedy slot corner, a pass-rush specialist DE who never starts) can swing a unit's actual game-day speed without ever showing up in this average. A team like the Falcons could easily be getting real snaps from faster players than this number credits them for.
I'll say the same thing I said about offensive speed: the "right" way to do this is to build a full-roster speed average instead of leaning on starters only, and I still haven't carved out the time to do that. Depth chart shuffles and a few in-season trades mean some of these numbers are already stale by the time this posts, too. Take it as a snapshot, not gospel.
The Final Analysis
Offense taught us that speed alone doesn't sell tickets or move the yardage needle much. Defense is a little more forgiving of the theory — the fastest defenses trend toward being better defenses, just not by nearly as much as scouting hype would suggest. The Cowboys prove speed can be a real weapon on that side of the ball. The Falcons prove you can still lead the league without it. As always: scheme, discipline, and depth chart luck are doing a lot more of the heavy lifting than raw SPD ratings get credit for.
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