Teams ran on Buffalo a lot though, their run defense was the worst in the league in YPA.
Also, they were behind a lot in games so opponents could run more. Compare that to us - we were ahead a lot so teams had to pass more against our defense (meaning fewer runs therefore fewer tackles for our DEs).
Well, that's true to some extent. Opponents ran on BUF 571 times and on the Pats 409 times and total scrimmage tackles (1044) was the same for both teams.
Interestingly though, 24% of rushing attempts on the BUF defense resulted in 1st downs - same percentage that the Pats defense gave up. Their 30-front (Stroud-LDE, Williams-NT, Johnson/Edwards-RDE) had about 23% of their total tackles (238 of 1044). FootballOutsiders shows them with a 50% success rate vs. power running (3rd-and-two or less), good for 2nd in the league, and a "stuffed" rate (runs for zero or negative yds) of 21%, good for 7th in the league. The problem with Buffalo's run defense was that nobody at the 2nd level could tackle and they gave up a lot of yards to RBs who got past the DL.
In contrast, total tackles by ALL EIGHT Pats D-linemen was 152 (15% of 1044). FootballOutsiders shows the Pats DL with a 32% success rate vs. power running (23rd in the league) and a stuff rate of 18% (21st in the league). The "success" of our 2010 run defense (in terms of YPA, but we were still only 16th in the league) was the result of our having LBs who can actually make tackles.
Bottom line, though, is that, aside from Wilfork (who had 57 of our 152 total DL tackles), our DL was a sieve.
The other takeaway point for me is that, when Buddy Nix talks about fortifying their run defense in the draft, he's probably talking about LBs rather than D-linemen.
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One further note about the 2010 D-line tackling (or lack thereof). In 2000-2009, D-line tackles were about 56% of runs against us, on average (never lower than 48%). In 2010, D-line tackles were 37%.