#137 | Pass Rush and Blitzing

[Rocketcan]

Hello Coaches!

Welcome to another Dev Diary for NewSim on SimFBA! This dev diary will delve into the changes to the pass rush and blitz systems for the v0.6.0 release of the NewSim engine.

Old/Current System:

There are several issues with the current system:

• Obvious meta of just blitzing passing teams as often as possible
• Unrealistically high number of sacks
• Blitzing automatically forces a pass rush situation in all but a few cases.
• Distribution on who was getting sack opportunities was off (too many DTs, too few DEs/OLBs/EDGE, etc.)
• The skill of the OL vs. DL has zero impact on the number of opportunities for sacks and only had a minimal impact on if a sack occurred. This would mean that teams with very talented DLs still needed to blitz to get sacks sometimes, even though they should be able to get pressure without blitzing as much.
•  Blitzing could only be countered with screen/quick plays
•  Run plays were unaffected by blitzing, an unrealistic result

A few key causes of these issues:

• The initial roll that determined pass rush situations resulted in very few chances.
• Pass rush mappings were not granular enough.
• Pass rush situations (especially when blitzing) often resulted in unbalanced matchups that lead to an unopposed defender free to rush the QB (i.e. the skill of the offensive line had zero effect).

Needless to say, I was not happy with the current system, especially because  it resulted in an obviously unrealistic and easily exploitable meta. The new system will aim to remove that meta, but more importantly, introduce a more interesting, realistic, and player-driven system.

New System:

The first problem with designing this new system for pass rushing was realizing that it was actually just a symptom of a larger problem regarding blitzing. Blitzing had no effect on the run at all (neither risk nor reward), and there was little downside to blitzing on a pass attempt as only quick passes and screens could counter the blitz. For example, there was no threat of a brilliant QB making a good hot read throw that beats the defense where it hurts most downfield. This needed to be changed to make blitzing a more thoughtful decision. Do you take a risk and blitz, hoping you don’t get burned trying to force a turnover or sack the qb? Or, do you play it safe and try to let your pass rush get home on their own and cover?

New Blitzing:

There will be no front-end changes to how coaches set up their teams’ aggressiveness and blitz rates on the gameplan page. All changes will be under-the-hood. Moving forward, blitzing will affect both rush and pass attempts.

Against the run:

• Blitzes against the run will now have three possible outcomes: Successful, no impact, or failure.
  • Successful
    • The blitz has disrupted the offensive play (i.e threw off the blocking scheme, beat the lead blocker to the hole, allowed a player to shoot a gap and get in the backfield, etc.) to the point where the defense has the chance for a big play.
    • There will always be a defender chosen who will have their run defense increased by two tiers. Therefore, there will be no cases where the offense has blocked the play perfectly and the ball carrier hits a wide-open hole.
  • No Impact
    • While the blitz did not directly succeed in disrupting the offense (i.e the OL picked up the blitz, the blitz hit a different hole from where the offense was going, etc.), it did not put the defense in a poor position, and the rest of the play will be resolved normally as if no blitz occurred. 
  • Failure
    • The blitz not only did not succeed, but it actively put the defense in a worse position (i.e. the QB saw the blitz coming and checked to a better play, the blitz was directed at the exact opposite place the run was going, or the blitz was executed poorly)
    • In the case of a failure, if any defender is chosen, they will suffer a two-tier drop of their run defense, and if the run is directed where there is no defender, then the run will receive an additional bonus on top of the normal one.
  • The success and failure chances will be influenced by the following factors:
    • Number of blitzers This currently corresponds to the blitz aggressiveness option in the defensive gameplan.
    • A higher level of blitz aggressiveness will result in a lower chance for a No Impact result and a higher chance of a Successful or Failure result. More cautious blitzes are more likely to have no impact, instead of a Successful or Failure result.
  • Blitzers’ attributes
  • Higher Run Defense, Football IQ, Speed, Agility, and Strength, will result in higher chance of a Successful blitz.

Against the pass:

• Blitzes against the pass will have the following effects:
  • The engine will determine if there is a pass rush attempt as these are not guaranteed during a blitz anymore A pass rusher is selected to be evaluated and will gain a bonus to their pass rush skill, simulating a one-on-one matchup against a single blocker (i.e. no chips, double teams, etc.) potentially from an advantageous angle, or something similar. The exact bonus is determined by the number of pass rushers. More pass rushers (e.g. more players on the LOS and blitzing) results in a higher bonus, but also adds risk in the form of a higher chance of uncovered receivers.
  • QBs will have a chance to skip any pass rush attempts by completing a Football IQ and Discipline check. If the QB succeeds AND there is an uncovered receiver, then the QB will throw the pass to the open receiver. If caught, the receiver will receive a bonus to yards gained. If the QB fails, then the pass rush attempt continues as normal with the pass rusher receiving a bonus based on the number of pass rushers. This check will not occur for normal (non-blitz) pass rush attempts.

New Pass Rush:

The following changes will be made to the base pass rush system:

• Automatic pass rush attempts will be removed
• Pass rush values have been expanded to more tiers to allow for more nuanced  differences between players of similar pass rush attributes. This will also make the Strength, Speed, and Football IQ bonuses to pass rush slightly more impactful  as the boosts are much more likely to result in a tangible benefit.
• Pass blocking values have also been made slightly more nuanced.
• Pass rush attempts will occur at a variable rate depending on the following:
  • Total Pass Blocking attribute of the OL
    • Higher Pass Blocking will result in fewer pass rush attempts
  • Total Pass Rushing attribute of all pass rushers (DL plus blitzers)
    • Higher Pass Rushing will result in more pass rush attempts
  • Type of pass play
    • Shorter passes will  result in fewer pass rush attempts than longer passes. Play Action will also increase the chance of a pass rush attempt.
• If a pass rush attempt does not occur, a pass play continues as normal.
• If a pass rush attempt occurs, then a pass rush matchup is generated between an offensive player and a defensive player. The matchup selected will be generated from the following table:

•  

Def Position	Off Position	% Chance
RE/ROLB	LT	11.20%
RDT/RE	LG	7.30%
NT/DT	C	7.30%
LDT/LE	RG	7.30%
LE/LOLB	RT	11.10%
1st Blitzer	1st choice: FB, If available   2nd choice: RB1 if available   3rd choice: No one (unblocked)	5.40%
2nd Blitzer	1st choice: RB1, if available 2nd choice: No one (unblocked)	5.40%
3rd Blitzer	Always unblocked	5.40%
RE/ROLB	LG	3.60%
RDT/RE	C	2.40%
NT/DT	RG	2.40%
LDT/LE	RT	2.40%
LE/LOLB	1st choice: FB, If available   2nd choice: Then RB1 if available,   3rd choice: No one (unblocked)	3.60%
1st Blitzer	LT	1.80%
2nd Blitzer	1st choice: RB1, if available 2nd choice: No one (unblocked)	1.80%
3rd Blitzer	Always unblocked	1.80%
RE/ROLB	1st choice: FB, if available 2nd choice: RB1, if available 3rd choice: No one (unblocked)	3.60%
RDT/RE	LT	2.40%
NT/DT	LG	2.40%
LDT/LE	C	2.40%
LE/LOLB	RG	3.60%
1st Blitzer	RT	1.80%
2nd Blitzer	1st choice: RB1, if available 2nd choice: No one (unblocked)	1.80%
3rd Blitzer	Always unblocked	1.80%

 

• A sack attempt will occur at a variable rate depending on the following:
  • Availability of a blocker on offense
    • If there is no blocker available, a sack attempt automatically occurs
  • Pass Blocking of the offensive blocker
    • Higher Pass Blocking allows for fewer sacks and results in more pancakes
  • Pass Rushing of the defender
    • Higher Pass Blocking results in more sacks and fewer pancakes against
  • Strength of the blocker
    • Higher Strength results in fewer sacks
  • Strength of the defender
    • Higher Strength results in more sacks
  • Speed of the defender
    • Higher Speed results in more sacks
  • Football IQ value of the defender
    • Higher Football IQ results in more sacks
• The chance of a sack attempt occurring ranges from 1-95%
  • Between 1-30%, a pancake occurs (currently, there is always a chance of a pancake, even for the best pass rushers vs. the worst pass blockers).
• During a sack attempt, the success rate is similar to the old system, but with the following changes:
  • The engine no longer takes the direct difference between the blocker’s Pass Blocking and the defender’s Pass Rush attribute as there are far more tiers of pass rush compared to pass block
  • In the new engine, an adjustment is made to any differences between the defender’s Pass Rush and the blocker’s Pass Block attributes to account for this change.
  • The chance of a successful sack attempt ranges from 1-95%
• There is now a 30% chance on all sacks for  another player to combine during the sack. This player will be chosen by a weighted roll against all pass rushers’ Pass Rush attribute. Players with a higher Pass Rush attribute will have a higher chance of being selected to receive a half of a sack.
• The maximum yards lost on a sack has been reduced  from 16 to 12, resulting in a lower average yards lost per sack.

That is it for this dev diary. Please ask any questions you have about the system below!

Until next time,

Rocketcan

[Sarge]

You're welcome.

[Wahoo]

FBIQ mentioned. FIELD GENERALS ON THE RISE