Background on Hali
Played 2006 & 2007 in a 4-3 at the left defensive end position. Hali registered 15 1/2 sacks his first 2 years from that position. In 2008 Hali became the Chiefs leading pass rusher (Jared Allen trade). Hali didn't get and worse...the circumstances changed. Team got younger and the production slipped to just 3 sacks. (2008 Chiefs set NFL record for lowest sack total for a season)
In 2009 the Chiefs changed defenses, and Hali was moved from the 4-3 DE position to the 3-4 OLB. Since the Chiefs have changed defenses...Hali has accounted for 35 sacks. Credit goes to Hali, but more goes into it.
Analysis
Hali game is based on momentum. Meaning he is an in-line player...he is dynamic when playing in a straight line. That ability translates well to the role of pass rusher...a role that ask a player to go the quickest route to point A to B. Physically his skill matches a role that is valuable in the NFL, and Hali is suited to be among the NFL elite.
Hali is a different player if asked to perform in space. If Hali didn't have the skill to rush the passer, it's certainly questionable if his ability to play in space would keep him on an NFL roster. The Chiefs roster is manned by players in Hali, Dorsey, Belcher, and Lewis that skill's translate to clearly defined roles. Credit should be given to Romeo for identifying the roles and putting the players in position.
The 35 sack number over the course of 3 seasons can be attributed to the scheme. Schemes are theories, and the theory for Kansas City is the 3-4 is the best defense. For Hali the 4-3 to the 3-4 switch changed one thing...his angle from point A to B. His role hasn't changed from his rookie year (contain)...but by changing the angle it allowed him to only amplify the things he did well.
As a DE Hali played either a 5 technique or the outside shoulder of the tackle (depending on strong side and 3 technique). That angle alone creates an easier block for the tackle. It requires Hali to have more power than a tackle to make plays, which he averages out equally yet has no distinct advantage. Moving Hali to the rush angles of a 3-4 OLB has allowed him to blend his physical ability by giving him further distance for momentum (in-line speed).
At 6'2" 270 pounds Hali is not especially quick (4.87 40 at Pro Day), or not powerful for his size. Through technique and effort he averages out to the most difficult blocking assignment in the NFL snap to snap. His consistency is what makes him great, even when he doesn't sack the QB he applies pressure.
For those that don't watch Hali then it is hard to understand what makes him an elite pass rusher. His technique is flawless, and his motor is non-stop. His sacks come from attrition, there are few left tackles that are going to answer the bell every play...which is required from preventing Hali from getting a sack. He sets a 4-5 second clock every play in the passing game for QB to get rid of ball...doesn't get the sack every time but keeps the clock set on opposing QB's.
Overall
As long as Hali is on the field he will be a disruptive force in the pass game. He is a liability in space, and serviceable in the run game. Not what scouts call a fluid athlete. He is a good blend of size, power, and speed. He is a technician and has some of the best hands in the game. Combined with his motor, he becomes an elite rusher.
