[Bumped, this is fantastic analysis - L8]
One of the most exciting features of the BC game was that NU actually got pressure on BC quarterback Chase Rettig. I was interested to find out what this means for the rest of the season, so I went back and looked at the three NU sacks and the intentional grounding penalty to see what NU did right. Video of the full game is on ESPN3, and several of these can be found as highlights at regular old ESPN.com.
1st sack: 1st and ten from the BC 43, 5:42 to play in the 2nd quarter, BC leads 10-3. Ball on the left hash, BC lines up in an offset I with the tight end and fullback both to the right (field) side. NU responds with their basic 4-3 under front (line shifted weak with the SLB lined up on the line over the TE) with the corners playing about 7 yards off and the safeties level at 10 yards deep. Before the snap, the strong safety leans forward and is about 9 deep at the snap.
BC runs play action to the offensive right, and the SS comes up hard on run action. The corners and FS drop into what appears to be a basic cover-3, splitting deep thirds. The BC receivers stem vertical while the TE and backs set up in the protection. The NU front initially bites on play action, but quickly recovers with 94 Vince Browne dropping into coverage on the offensive left and the SS heading to the offensive right flat. The coverage appears to be a basic 3-deep zone with the SS and RDE covering the flats while the DTs, LDE, and SLB rush. The HB quickly leaks through the middle of the line to serve as a checkdown, leaving BC with 7 to block 4. The right receiver's route disappears from the TV view while Momah appears to curl at around 12 yards where three NU defenders converge on him. The back briefly comes open in the middle but Rettig never looks to him. The pocket initially sets up nicely, but Rettig begins to run without being directly pressured. Once Rettig starts moving, he runs into pressure and DiNardo eventually breaks free for the sack.
Analysis: This play appears to have been an attempt to go deep off of play action. The WRs were well covered and Rettig didn't look to his checkdown while he was open. Once plan A had failed, Rettig started to move without much purpose until NU's rush arrived to finish him off. Good effort in finishing the play by DiNardo, but this sack is entirely Rettig's.
2nd sack: 2nd and 12 from the BC 48, 9:29 left in the 3rd quarter, NU leads 17-10. Ball once again on the left hash, BC lines up in a singleback set with a tight end and an h-back to the offensive right. The flanker to the right of the formation lines up with a fairly tight split. NU is in a 4-3 under front with the CBs playing seven yards off, WS ten yards off almost directly in front of the ball, and SS walking down towards the flanker at the snap. Rettig takes a straight drop, the TE immediately releases, and the h-back either checks for blitzers before releasing or just takes a drop step to better time his route. Once again the RDE (Browne) drops into coverage while the SLB (Ben Johnson) rushes. Coverage appears to be the same as the first sack, 3-deep with the SS and RDE covering the flats. BC has six blockers to block four NU rushers.
The WRs head deep out of the TV view. The tight end curls about eight yards deep directly over where the flanker lined up while the h-back leaks to an open spot on the offensive left underneath the coverage. Coverage appears solid, while the protection quickly breaks down. The HB picks up Johnson and is immediately driven back, while the defensive linemen slant to the offensive left. 93 Niko Mafuli, lined up at nose tackle, disengages from the first blocker and loops to his left just as Rettig reacts to Johnson's success by trying to escape out of the pocket to his right. He sees Mafuli running free and Johnson moving to the other shoulder of the HB, reverses direction, and immediately runs into 97 Tyler Scott who has defeated a block and cleans up with the sack.
Analysis: good team pressure here. Ben Johnson's success against the HB forced Rettig out of the pocket while the two linemen both got free to attack the QB. This is the kind of pass rush NU needs out of the base defense.
3rd sack: 1st and ten from the BC 32, 9:00 left in the 4th quarter, NU leads 24-10. Ball on the right hash, BC lines up with a singleback and three wide receivers, two to the field and one with the tight end to the boundary. NU comes out in a 4-2 with the line shifted to the weak side of the formation with a man lined up about five yards off of the inside receiver, the SS moving into the box, the LCB 6 off of the lone receiver, the WS ten yards over the inside receiver to the two receiver side, and the RCB nine yards off the outside receiver.
Rettig fakes to the HB heading left at the snap while the receivers head downfield. The left LB 51 Bryce McNaul and the SS 10 Brian Peters blitz. The TE engages the LDE, the RT heads for the blitzing LB, and Peters storms through the hole in BC's protection. McNaul is never fully blocked by the RT and drives him back with his right shoulder free a step behind Peters. Rettig never has a chance to set up after the run fake and goes down for the sack. The blitz appears to have been a five man fire zone with the LDE dropping off after initially engaging the TE. Coverage was likely three deep, three under.
Analysis: a perfectly executed blitz to pick up the sack. BC's protection failed to account for Peters, allowing him to pick up the sack before Rettig could even get set in the pocket. NU's blitz schemes weren't overwhelmingly successful against BC, but in this case Peters came completely free and McNaul took advantage of a bad set by the RT to add to the pressure.
4th sack (Intentional Grounding): 2nd and 6 from the BC 40, 1:16 left in the 4th quarter, NU leads 24-17. Ball on the left hash, BC hurries to the line after a short completion with three wide and a single back. TE and one receiver left, two receivers right, HB to Rettig's left in the shotgun. NU corners give ten yards, WS almost twenty deep in the middle of the field, with a four man line.
TE releases immediately while the back stays in against a four man rush. The TV camera zooms in quickly so it is difficult to tell anything about the coverage other than that it is zone, though the pre-snap safety positioning suggests another three deep coverage. DT 42 Kevin Watt shoots the offensive left A-gap and the LG barely gets a hand on him as he charges for Rettig. Rettig slides to his left and tries to throw the ball away. He may have escaped the pocket, but the ball clearly does not reach the line of scrimmage and he (eventually) gets flagged for intentional grounding.
Analysis: a fantastic individual rush from Kevin Watt. The OG set up to engage him and Watt blew through the gap before the guard could move his feet to cut him off. Rettig had no chance to get the ball away (legally anyways) before he went down.
Conclusion: Rewatching these plays, I was reassured about the state of NU's pass rush. The first sack was definitely on Rettig, and the second could be considered his fault for being indecisive when faced with the initial pressure. I was still impressed with the quality of the rush on the second sack, with Johnson creating the initial pressure and both Mafuli and Scott getting free to help out. The intentional grounding call on the final drive resulted from the kind of individual pass rush success that a defense needs to have success without excessive blitzing. If NU can come up with one perfect blitz per game and a few good individual pressures, the defense should be much improved.
I also was interested to discover that Browne was dropping into coverage frequently in what appeared to be base defense calls with Johnson rushing from his stand-up spot at the other end of the line. This is something I may investigate further this season to see if these plays were anomalies or just how NU's coaching staff wants to play from the 4-3 under front.