You will likely hear tomorrow about the "Wide Nine" front the Eagles use. Let us go over exactly what that means. On the defensive line, where the player lines up is known as a technique. If you line up across from the center, you are playing what is known as the zero technique. The further you get from the center, the higher number technique you are playing. If you are on a guard's inside shoulder, you are playing the one technique. Across from the guard is the two technique. On the guard's outside shoulder is the three technique. The tackle's inside shoulder is the four technique. Directly across from the tackle is the five technique. On the tackle's outside shoulder is the six technique. The tight end's inside shoulder (or where it would be if there is no tight end on your side of the field) is the seven technique. Directly across from the tight end is the eight technique. The tight end's outside shoulder is the nine technique.
Below is an illustration.
The Eagles are somewhat unique in that they have both defensive ends line up at the nine, which is where the name Wide Nine comes from. Most 4-3 teams on non obvious passing downs have at least one end play the six or the seven technique. The reason is simple spacing.
The top is an example of one Wide Nine look. The bottom is a look where one end plays the seven and another plays the six. The Wide Nine creates enormous gaps against the run. Conversely, it gives the ends a clearer shot to speed rush and get up the field against the pass. There is a straight line path to the quarterback that forces the tackles to make a difficult deep drop, get to the spot first, and gain leverage.
The Wide Nine requires excellent tackle play. Two teams that have successfully employed it in recent years are the Tennessee Titans and the Detroit Lions. They had Albert Haynesworth and Ndamukong Suh, who could control large areas of the line to make up for tackles lined up far outside. It also helps to have linebackers who can work in traffic. The Eagles have not gotten this kind of play so they have struggled against the run this season. This is why the Jets might have problems with a pass rush but a good chance to have success on the ground.