Yes, each team currently uses their own balls. Interestingly, the change was spearheaded by P. Manning and Brady back in 2006. I kind of remember it being referred to then as the Manning/Brady Rule.
http://www.washingtonpost.com/blogs/...d-deflategame/
IMHO, if Brady is so adamant about how his balls feel, he would have noticed they were 2lbs under inflated...imagine a pro golfer being handed a different driver than they use every day. They would notice it in a second.
I predict a severe penalty after the Super Bowl, Belecheck getting suspended, possibly (but unlikely) Brady, draft pick(s) and fines. Too big of a story and second time getting caught.
