I saw an example of a 49er defensive play where the rules of pattern matching are much better explained by this article
. The article has already been linked on page 10 of this thread. For this play, the pattern matching rules for the strongside CB and the SS (from the article) are well represented.
In case you don't want to click the article, pattern match is playing man coverage after the WRs have made breaks in their routes. The coverage starts off looking like zone, then morphs into man coverage once the WR routes are distributed.
It's a generic 'pick a side' play as GB will run the smash concept (zone buster) on the side where Nnamdi (#28) is. On the other side, they will get a rub concept (man buster).
49ers will come with cover2 pattern match.
When calling pattern match, the defense will designate numbers for the WRs from the outside to the inside, on each side of the field. These numbers help the defenders apply the rules of pattern matching.
Rodgers drops back and looks to his right. This shows he thinks it's zone coverage because he looks to the zone buster side. The article has examples of cover1 pattern match. Since the 49ers are in cover2 here, the article isn't going to perfectly describe what the 49ers are doing.
In this play, Nnamdi will adhere to the rules of the strongside CB (from the article). Bow will follow the rules of the SS from the article. It does not look like Willis is a part of the pattern matching, as he seems manned up on the #3.
The play starts:
Nnamdi plays with a cushion so that he can read the route stem of #1 as well as the dropback of the QB. Bow is also reading #1 while failing to re-route #2. When watching the GIF later, you'll see that Willis is the defender that partially re-routes #2 as he crams himself in between #1 and #2. That will suffice. As long as someone attempts to re-route #2, the coverage call will start off well.
This is what Nnamdi (CB) is reading: In the diagram below compared to the play in this example, the WR is #1, the TE is #2.
#1 has broken on his curl route and is no longer going vertical. This will cause a chain of events to occur.
Bow has now identified his man coverage assignment and will man up on #1.
Nnamdi now must read #2. If #2 does not go vertical, then Nnamdi is free to jump #1's route. If #2 continues vertical, then Nnamdi will man up on #2.
Whitner is reading #2. If #2 breaks inside, Whitner will jump any inside breaking route. I'll get back to Whitner/Reid later in the post.
#2 does go vertical and has his corner route easily defeated by Nnamdi and Whitner. Bow has #1 covered. At this point, Rodgers has found nothing on the Smash concept side, is pressured, and starts to scramble.
The Smash concept is thoroughly defeated.
When the play starts out, you wouldn't think that Nnamdi would end up covering the slot WR, but that's what can happen in pattern matching. The defense doesn't know who they will end up covering, it's up to the offense to determine this.
This is pre-snap of the play. Check out the amount of communication going on between Whitner, Nnamdi, Bow, and Willis. Then when the WR at the bottom of the screen goes in motion, Brown and Rogers sort out who it covering who as they switch off assignments.
Going back to Reid/Brown at the bottom of the screen:
Notice how deep Reid is playing, and he's backpeddling. Compare to Whitner, who is flat footed and waiting for the #2 on his side to get closer. Brown is playing outside leverage, over the top. Brown is depending on Reid to cover any inside breaking route.
When the #2 on Reid's side breaks inwards on his deep in route, Reid is in no position to properly cover the #2. #2 deserves a target from ARodgers, had Rodgers not been pressured.
Fast forward to week 11. This play was broken down in post #258. The two WRs on Reid's side are running very similar routes to the play above. The 49ers are also in cover2 pattern match. Notice the depth at which Reid is playing. Reid is in a good position to jump any inside break from the yellow WR. The CB (TBrown) is playing with outside leverage, over the top - just like the play above.
When the WR breaks inwards on his deep in route. Reid is in a much better position to jump the route, while Brown takes over for Reid's deep zone.
This is player growth from Reid.
This goes back to the two newest members of the secondary who are being relied upon to take on significant roles, Ward and Bethea. I have no idea whether these two guys are familiar with pattern match coverage. Bethea is a seasoned vet so he may have done it all at this point, though he mainly played straight up cover2 man in IND last season. I have no idea what Ward played in college. Donatell/Fangio have their work cut out for them to get these guys up to speed in order for Fangio to have the entire defensive playbook at his disposal.