Again, an award that Colin McCarthy would have run away with if he would have been starting from week one. Since he was not, here are your candidates:
Ryan Kerrigan- Kerrigan burst onto the scene in a big way in week one when he intercepted an Eli Manning pass and ran it in for a touchdown. That was his only interception of the season, but he did add 7.5 sacks.
Von Miller- Miller made a huge impact on the Broncos defense this season. He had 11.5 sacks and two forced fumbles last season. You could argue that he was more responsible for the Broncos' run the the playoffs than Tim Tebow was.
Patrick Peterson- Trevor's boy Peterson did not make a much of an impact as a corner, but he was a weapon on special teams. Peterson average 15.9 yards per punt return. That is better than even Marc Mariani!
Aldon Smith- Smith is probably who ends up winning this award. He was a terror all season long. He ended up with 14 sacks and 2 forced fumbles.
Let me know who I tragically left off the list in the comments.