I've singled out Alonso b/c there is a constant and prevalent misconception that he is an asset to our defense. People notice his splash plays that happen every few or so games, but they don't recognize his many errors and lack of significance in all the other snaps that occur in every game. I have often been berated (see quoted post above) when I point out those issue in mere words, so I felt a thread with visual evidence was worthy to proceed with.
You're are correct that Harris is a culprit for attacking so strongly upfield and lacking awareness to a possible run (a knock on him in college as well), but that doesn't exempt the rest of the 10 defenders from following their assignments and making the proper play on the ball.
There are two types of run defense philosophies, Force and Spill. Our run defense philosophy is Force, meaning we contain the edges and funnel the runner inside to more help. A run defender's responsibility in our scheme is to have an outside-in relationship to the ball. In the play we are discussing Alonso must continue to pursue the outside edge in order to force the ballcarrier back inside to the help that is flowing toward the ball.
Here is the play being discussed.
In that clip Alonso clearly does not adhere to our run principles, takes an inside path to the ball, gives up the edge, and allows a 26 yard gain. That's unacceptable regardless of whoever else might have missed an assignment.
