There were a few things the Niners did several times very effectivley to keep the strong front seven of the Lions from hammering Smith. Given the talent the Lions have, they weren't always successful, of course.
To illustrate, I have broken down plays where the Niners were able to beat the Lions' defensive line—and one where they couldn't, and why that one instance worked for the Lions where others failed.
On this first play, a run by Frank Gore from almost his own end zone, Corey Williams is going to come hurtling in to get Alex Smith or stop the run depending on the play.
The setup is pretty standard, though you see a receiver coming in motion to help block.
As Williams shoots the gap, the receiver cuts across behind the line and blasts him, sending him away from Gore, who then bursts through the same hole for a big gain.
This sort of play jumped out at me a few times, in which the Lions got quick penetration, but either the play was designed to allow that upfield surge and move the other way, or the Niners had accounted for it and left a guy to seal off the penetrating Lion.
On this next play, the Niners did a variation on the same theme. They kept in seven players to block for Smith.
You can see the ultra-clean pocket he has to sit in and wait for an opening or move and get rid of the ball, if need be. The Lions only rush four on the play, so it's easy to keep Smith upright, but had they rushed more, the Niners had the necessary number of blockers to slow them down.
In order for this to pay off though, Niner receivers have to get open, and that happened way too often. The Lions' secondary had some issues with all sorts of routes, especially short and intermediate, though longer ones gave them fits, as well. The secondary, which is a little beat up, struggled, especially safety John Wendling, who was smoked for an early Vernon Davis touchdown.
When the secondary played well, the Lions were able to pressure Smith, and—as in the last play we're looking at—sack him.
On this play, the Lions are again rushing four, dropping the rest of their defenders into coverage. They do an excellent job of bracketing the receivers early—the receivers aren't covered by just one but, instead, a combination of three or four defenders.
Smith has nowhere to go, and it only gets worse as the two receivers make their way downfield, surrounded by six Lions defenders.
Smith tries to flee, but he's soon run down by the Lions' pass rush.
The only thing I can't quite wrap my head around is why Smith didn't dump the pass off to his two open (highlighted) receivers. One was covered, though a quick pass should have made it to him, but the receiver in the center of the field is completely open.
My only thoughts are that Smith didn't see either of them, that there was something he saw (or thought he saw) that isn't on the film or he wanted to see if one of the receivers downfield could break free from the coverage while he was scrambling.
This is a coverage sack, pure and simple. As talented as the Lions' defensive line is, they don't make that sack if the coverage doesn't do it's job.
Unfortunately for the Lions, more often than not, the secondary wasn't able to keep its men under wraps, so Smith and the Niners were able to complete passes.
The Titans are up next and while Tennessee isn't all that great offensively, the defense can be solid. The Lions will have to make sure they don't repeat the tendencies we saw here, if they want to get back on the right path towards the playoffs.
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