I would probably put Collins at 3;
Rodgers
Mathews
Collins
Jennings
Sitton
Raji
Collins is the best Safety in the NFC, I cant think anyone better, and a top 5 Safety in the league for sure. Ed Reed is easily better, and Polomalu probably, but is hurt too often to really say he is definitely better. Possibly top 3/borderline all pro? Not too bad for a 2nd round pick, with this mentality he should be placed above Jennings.
Collins finished 3rd in the all pro voting at S, which goes along with my thinking. Jennings 7th, which I dont think is the best gauge, but it goes to show that Collins is pretty much regarded as the 3rd best S in the league.