by Aaron Schatz

At this point, most football fans understand that tackles are a bad way to measure defensive backs. Often when a defensive back gets a tackle, he's getting it because he screwed something up in coverage. The defensive back who leads the league in tackles is probably a guy who isn't that good at his job.

Well, not necessarily, because tackles come in all different flavors. First of all, there's a difference between getting a tackle on a running play and getting a tackle on a passing play. On a passing play, there is certainly a difference between getting a sack and taking down a receiver after he catches the ball. If he catches the ball, there's a difference between getting a tackle on a guy you were supposed to cover and cleaning up after somebody else's mistake. And even if you tackle a guy you were covering, there's a difference between a tackle that shows bad coverage (say, after a 15-yard gain on first-and-10) and a tackle that shows good zone coverage (say, after an eight-yard gain on third-and-10).

For example, Morgan Burnett led all defensive backs with 121 tackles; that includes both solo tackles and assists, but not tackles on special teams. However, Burnett wasn't a particularly bad player last year, as a breakdown of those tackles will demonstrate. We can start by removing 57 tackles on run plays, fifth in the NFL, and two sacks. That leaves us with 62 tackles on pass plays, which is tied for fifth. However, 17 of those tackles prevented a gain that would pass our baseline for offensive success. Burnett ranked fourth among safeties in such plays, which we can call "pass-tackle stops." And 27 of the remaining 45 tackles were on plays our game charter either listed with another player in coverage or as either "Hole in Zone" or "Uncovered."

So I thought it might be interesting to look at which players last year racked up tackle numbers by cleaning up mistakes by his teammates, as well as screens, dumpoffs and plays where the opposing quarterback had enough time in the pocket to find the holes in zone coverage.

Here are the top 20 players from last season who had a tackle or assist on a pass that we considered an offensive success, without being listed in coverage by our game charters. I will also list the average yardage of these receptions.

Top 20 Defenders on "Clean-Up Tackles," 2012 Player Team Clean-Up

Tackles Avg Yds 20-R.Jones MIA 33 14.4 42-M.Burnett GB 32 16.4 54-L.David TB 32 9.1 20-R.Barber TB 31 11.5 31-D.Whitner SF 31 11.6 32-E.Weddle SD 31 15.8 58-T.Davis CAR 29 7.5 30-C.Clemons MIA 29 18.0 26-A.Winfield MIN 29 8.8 52-J.Durant DET 28 8.6 Player Team Clean-Up

Tackles Avg Yds 59-L.Kuechly CAR 28 10.5 27-Q.Mikell STL 28 12.9 33-T.Branch OAK 28 16.1 22-H.Smith MIN 28 12.3 31-C.Finnegan STL 27 9.7 52-C.Greenway MIN 26 7.5 52-P.Wheeler OAK 26 11.1 43-C.Dahl STL 25 18.3 50-C.Lofton NO 24 8.9 31-B.Pollard BAL 24 16.9

Another way to look at this would be to look at just cleaning up after mistakes in coverage by removing plays marked "Uncovered" or "Hole in Zone." Here are the players who led the league in those such tackles; as you can imagine, they are all safeties.

Top 20 Defenders on "Clean-Up Tackles"

without Uncovered/Hole in Zone Passes, 2012 Player Team Clean-Up

Tackles Avg Yds 31-D.Whitner SF 20 11.7 30-C.Clemons MIA 18 19.6 42-M.Burnett GB 18 21.3 28-T.DeCoud ATL 18 17.5 20-R.Jones MIA 16 14.4 20-R.Nelson CIN 13 18.8 41-M.Williams WAS 13 15.2 47-C.Conte CHI 13 25.4 31-K.Chancellor SEA 13 15.3 25-R.Clark PIT 12 17.7 41-A.Bethea IND 12 17.3 38-D.Goldson SF 12 12.0 22-H.Smith MIN 12 13.6 24-M.Barron TB 12 19.1 43-M.Jennings GB 12 15.1

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The top tacklers in this category among cornerbacks were Atlanta nickelback Robert McClain (11), as well as Corey Webster, Jason McCourty, and Josh Wilson (nine each). The top tacklers among linebackers were Daryl Washington (10) as well as Justin Durant and Craig Robertson (nine each).

Another way to look at this is to see who makes the most tackles on pass plays overall, no matter who is in coverage or how long the reception was. Pretty much every defensive stat category in the NFL last year was led by either J.J. Watt or Luke Kuechly, and this one was no exception, as Kuechly had 69 pass tackles. He also was second in the league with 26 "pass-tackle stops," behind only his teammate Thomas Davis. Here is a list of the top defenders in pass tackles, along with how many stops they had and their pass-tackle stop rate. The league average was 33 percent for linebackers, 23 percent for cornerbacks, and 19 percent for safeties.

Total Pass Tackles by Linebackers, 2012 Total Pass Tackles by Defensive Backs, 2012 Player Team Pass

Tackles Pass-Tackle

Stops Pass-Tackle

Stop Rate Player Team Pass

Tackles Pass-Tackle

Stops Pass-Tackle

Stop Rate 59-L.Kuechly CAR 69 26 38% x 31-C.Finnegan STL 68 16 24% 52-C.Greenway MIN 61 20 33% x 33-C.Tillman CHI 65 17 26% 54-L.David TB 60 21 35% x 30-J.McCourty TEN 65 15 23% 59-L.Fletcher WAS 60 17 28% x 42-M.Burnett GB 62 13 21% 58-T.Davis CAR 55 32 58% x 23-D.Hall WAS 62 13 21% 52-P.Wheeler OAK 55 21 38% x 29-C.Williams BAL 61 6 10% 58-R.Maualuga CIN 55 19 35% x 20-A.Cason SD 59 6 10% 55-V.Burfict CIN 54 16 30% x 26-A.Winfield MIN 58 17 29% 50-K.Wright SEA 53 14 26% x 41-R.Harper NO 57 10 18% 58-J.Dunbar STL 49 18 37% x 22-B.Skrine CLE 56 12 21% 53-C.Robertson CLE 49 17 35% x 20-R.Barber TB 55 22 40% 52-P.Willis SF 48 19 40% x 31-K.Chancellor SEA 55 16 29% 56-P.Riley WAS 47 15 32% x 31-D.Whitner SF 55 11 20% 51-J.Mayo NE 47 14 30% x 32-C.Vaughn IND 55 11 20% 50-J.Freeman IND 46 14 30% x 23-T.Newman CIN 54 14 26% 50-C.Lofton NO 46 13 28% x 26-J.Wilson WAS 53 15 28% 55-J.Laurinaitis STL 46 11 24% x 22-H.Smith MIN 53 10 19% 52-D.Jackson CLE 45 14 31% x 21-J.Jenkins STL 53 9 17% 50-R.Allen JAC 45 9 20% x 23-Q.Jammer SD 52 11 21% 58-K.Dansby MIA 44 13 30% x 24-J.Norman CAR 51 8 16%

Davis' 32 stops in 55 pass tackles made him one of only two players last year with at least 20 pass tackles and a 50 percent pass tackle stop rate. The other was Stephen Tulloch of Detroit, at 51 percent. Here are the best and worst pass-tackle stop rates with a minimum of 20 pass tackles.

Best Pass-Tackle Stop Rate by Linebackers, 2012 Best Pass-Tackle Stop Rate by Defensive Backs, 2012 Player Team Pass

Tackles Pass-Tackle

Stops Pass-Tackle

Stop Rate Player Team Pass

Tackles Pass-Tackle

Stops Pass-Tackle

Stop Rate 58-T.Davis CAR 55 32 58% x 21-J.Lacey DET 26 11 42% 55-S.Tulloch DET 43 22 51% x 20-R.Barber TB 55 22 40% 50-N.Barnett BUF 33 14 42% x 25-C.Harris DEN 35 14 40% 59-D.Ryans PHI 29 12 41% x 29-E.Berry KC 30 12 40% 95-M.Kendricks PHI 29 12 41% x 26-E.Lankster NYJ 21 8 38% 54-B.Urlacher CHI 29 12 41% x 29-C.Hayward GB 32 12 38% 54-D.Hightower NE 22 9 41% x 27-T.Wilson NE 24 9 38% 52-P.Willis SF 48 19 40% x 27-P.Lee OAK 24 9 38% 54-D.Levy DET 33 13 39% x 31-J.Byrd BUF 39 14 36% 52-P.Wheeler OAK 55 21 38% x 24-A.Jones CIN 31 11 35% 51-P.Posluszny JAC 42 16 38% x 23-M.Trufant SEA 31 11 35% 59-L.Kuechly CAR 69 26 38% x 29-L.Hall CIN 26 9 35% Worst Pass-Tackle Stop Rate by Linebackers, 2012 Worst Pass-Tackle Stop Rate by Defensive Backs, 2012 Player Team Pass

Tackles Pass-Tackle

Stops Pass-Tackle

Stop Rate Player Team Pass

Tackles Pass-Tackle

Stops Pass-Tackle

Stop Rate 56-A.Ayers TEN 34 5 15% x 43-G.Sensabaugh DAL 34 1 3% 54-J.Brinkley MIN 35 6 17% x 24-A.Jefferson MIN 31 1 3% 50-R.Allen JAC 45 9 20% x 24-M.Barron TB 42 2 5% 43-B.Scott BUF 28 6 21% x 42-I.Abdul-Quddus NO 26 2 8% 50-J.Anderson CAR 23 5 22% x 25-P.Chung NE 25 2 8% 52-D.Harris NYJ 34 8 24% x 28-S.Gregory NE 25 2 8% 53-N.Roach CHI 21 5 24% x 43-A.Black TB 25 2 8% 55-J.Laurinaitis STL 46 11 24% x 28-T.DeCoud ATL 37 3 8% 55-B.Spikes NE 33 8 24% x 42-K.Coleman PHI 35 3 9% 58-D.Washington ARI 32 8 25% x 28-U.Young CLE 23 2 9% 53-J.McClain BAL 24 6 25% x 30-C.Godfrey CAR 34 3 9% 59-B.Jones GB 24 6 25% x 27-M.Jenkins NO 45 4 9% x 38-T.Williams GB 45 4 9% x 33-C.Crocker CIN 22 2 9% x 25-T.Brown SF 43 4 9% x 29-C.Williams BAL 61 6 10% x 31-D.House GB 20 2 10% Note: minimum 20 pass tackles. x 20-A.Cason SD 59 6 10%

I added a few names to the bottom of the "worst pass-tackle stop rate" table for defensive backs; as you might imagine, most of the worst rates belong to free safeties, so I wanted to make sure we had a few other cornerbacks listed for those curious.

Finally, what about the opposite of the clean-up tackle? Who had the most tackles on passes where he himself was in coverage? If you remember reading the AFC playoff previews, you may be able to guess the answer. It's Cary Williams, formerly of the Baltimore Ravens and now of the Philadelphia Eagles. He had 46 such tackles last year. No other player had more than 37.

Top 20 Defenders, Tackles on Own Coverage, 2012 Player Team Tackles Avg Yds 29-C.Williams BAL 46 12.7 33-C.Tillman CHI 37 10.4 20-A.Cason SD 37 10.8 32-C.Vaughn IND 34 11.6 22-B.Skrine CLE 34 11.9 24-J.Norman CAR 32 13.3 30-J.McCourty TEN 30 12.0 23-K.Lewis PIT 30 11.4 24-S.Smith MIA 30 12.4 23-D.Hall WAS 29 17.8 Player Team Tackles Avg Yds 24-S.Brown CLE 29 12.1 25-T.Brown SF 29 13.8 38-T.Williams GB 29 12.4 24-J.Joseph HOU 28 13.3 21-J.Jenkins STL 28 10.9 23-C.Webster NYG 28 14.4 23-D.Robinson ATL 28 15.1 21-P.Robinson NO 27 16.0 26-T.Jennings CHI 27 13.2

What about the cornerback coverage stats, the ones that come straight from charting and don't have anything to do with the play-by-play? We'll run the final adjusted 2012 numbers in articles next week.