With the departure of John Abraham and the arrival of Osi Umenyiora, Kroy Biermann's role is a debatable issue once again. There's a decidedly convinced contingent that believes he can't start opposite Osi. I'm not going to say I disagree with those folks, but I'll say this: even if we don't bring back Abe, the sky won't fall.
Biermann is an important figure in the Mike Nolan defense. We all know the Falcons favor zone coverage, which necessitates a spy, especially against the option. Biermann has filled that role admirably, while providing capable and consistent run defense. Heck, he even plays a little safety on third and long. He's versatile, and that's uncommon in the modern NFL.
The Falcons will draft a defensive end in the early rounds later this month, of that I'm sure. Some combination of that rookie, Osi, Biermann, Cliff Matthews, and Jonathan Massaquoi will probably be it for the Falcons in 2013. And that's okay in my opinion.