Everyone wants stats that no one keeps about how far a tackle is made downfield on a running play once the credited tackler gets there.
If you want individual linebacker examination, see:
http://www.advancedfootballanalytics.com/index.php/home/stats/defensive-players/linebackers
Advanced Football Analytics has JL as the #2 linebacker in the NFL last season -- which is crazy since I think last year was his worst season. He was hobbled and a step slow. His individual ranking at that site has fluctuated from being unranked as a rookie to 10th-30th range to second best in the NFL, which to me speaks volumes about trying to measure this stuff. There's no year-to-year sticky correlation because the "true skill" is drowned out by all the variable noise.
The problem with *individual* rankings is that it runs into the PFF money machine fallacy that tries to sell (literally) the impossibility of objectively grading individuals in football, the ultimate team sport. Every time someone does something "successful" on a given play, it's because anywhere from 1-10 other teammates on the field did something successful to allow that guy to be successful... Not to mention that every outcome could be viewed from the opposite perspective that instead of someone's "success" it might have been 1-11 opposing players screwing up instead as the primary reason...
So your desire to know how far downfield JL makes tackles would be polluted by all those contributing variables, not to mention the offense/defense scheme, quality of opponent, field conditions, etc., and most importantly context -- Imagine you read in a play-by-play that JL made a tackle on a 20-yard gain and say "ha! see I told you he only makes tackles 20 yards downfield!" when in reality it was a sweep away from him blitzing from the opposite side, and you're bad-mouthing him for busting his ass running 60 yards chasing down the carrier to save a would-be touchdown.
If you want more imperfect stats, I already posted the "stuffs" totals for JL showing him way better than ESPN's wet dream linebacker (of course ESPN gets a chubby any time a Whiner is anything better than replacement player level). You can also see Football Outsiders defensive line stats "(more accurately, defensive front seven stats)":
http://www.footballoutsiders.com/stats/dl
Here are the Rams front 7 rankings in:
- overall rank
- power rank (Percentage of runs on third or fourth down, two yards or less to go, that achieved a first down or touchdown. Also includes runs on first-and-goal or second-and-goal from the two-yard line or closer.)
- stuffed (Percentage of runs where the running back is tackled at or behind the line of scrimmage)
BEFORE JL ARRIVES
Year -- Overall Ranking -- Power Rank -- Stuffed Rank
2008 -- 32nd (worst in NFL) -- 17th -- 22nd
AFTER JL ARRIVES
Year -- Overall Ranking -- Power Rank -- Stuffed Rank
2009 -- 22nd -- 13th -- 19th
2010 -- 18th -- 6th -- 11th
2011 -- 23rd -- 8th -- 19th
2012 -- 2nd -- 13th -- 3rd
2013 -- 5th -- 4th -- 2nd
2014 -- 3rd -- 4th -- 5th
JL does something right. Maybe every time he makes a tackle he doesn't get a hand-job from Chris Berman and the highlight shown 1,000 times like Willis, that's not his fault. The front 7 has been top-5 three years running and looks to get even better this year, I'll happily take it and JL barking out the orders.