Bud Foster is GREAT defensive coordinator
But his scheme is built for the college game and despite what the rumors are, he rarely blitzes anymore
His D's are built around dominant d-lines that can apply pressure from the DE spot, 8 in the box to stop the run and then zone D on 3rd down
The WLB in his scheme is called a "whip" and the SS a "rover" both hybrid LB/DB type players
It is not quite a 4-3, but its based off that scheme
He generally does not bring pressure but relies on a dominant D-line to get the job done. The players gang tackle every play and its a swarming D
The weakness to it? A very strong passing game that can provide protection. If you can pass protect against the VT d-line you can throw it down the middle of the field a bit. Its gotten better over the years because of better athletes on VT's D, but the schematic weakness is there
I for one would be a miserable Commanders and Hokie fan if Bud Foster left and went to Dallas
And Al Groh of UVA is buddies with Parcells