From what I understand, the NUMBER of tackles that are "Credited as Tackles" is FINALIZED not by NFL game day spotters, but the final decision based on the game film viewed by the teams caoching staff..
The number of tackles recorded can be altered by the team's coaches that make that determination based on looking at the film after the game.
For example... A team (Coaching Staff.) may take away a tackle from a player and change it to an assist after looking at the game film.
I have heard that some coaches actually use that stat to encourage, motivate, and or punish a player (for blowing an assingnment.) by altering the numbers the team sets for the NFL stats on credited tackels.
Let me, give you an analogy.
Next year, first game... New coach MM takes a look at game film and decides that Collins should have never made that tackle becuase he blew his assignment. A punishment if you will. MM can then make an adjustment to the official tackle stat and change it to an assisted tackle.
Hertofore, Collins would not be credited with the tackle by the coaching staff, and thus it will not be counted and recorded in the NFL logs as an official tackle but an assisted tackle.
On the other hand there are coaching staffs that will boost a players official tackle numbers by playing favorites and reporting to the NFL official stats that player X should have been credited with an assist on the tackle.
The key number to look at in defensive tackles made is the number of SOLO tackles. Solo tackles are untouchable, and can not be taken away from the stats.
NOW Lets look at this year.
Nick 63 - 21 - Total 84
Troy 73- 18 - Total 91
The question is how many of those tackles officially recorded after the coaching staff looked at film are padded, and or reduced for motivation during the film session.
Either way you gotta Love what Collins is bringing to the team, and he is going to be a Pro bowl player often.
RP