Gross has already indicated that he'll either play for the Panthers or retire.http://profootballtalk.nbcsports.com/20 ... next-year/
The issue with Collins is that Cincinnati is probably going to want to re-up him to a long-term deal because Whitworth is 32 and nearing the end of the road. If they think Collins can be that long-term option, and here's been there for 6 years, so they probably have a good idea if he is, then he'll likely stick there.
If the Falcons really want to restructure a deal, it will be Matt Ryan's contract. He is due a $12 million option bonus on the 5th day of hte league year. That is going to basically be a $2.4 million extra hit on their cap this year once it goes into effect ($12M prorated over 5 years = $2.4M). The Falcons might be smart to defer that bonus to next year, and subsequently guarantee his $9.5 million base salary this year for both skill and injury (It's only currently guaranteed for injury) as. That would be an easy way to save $2.4 million against this year's cap.
Or of course you can do the tried and true method of just lowering Ryan's base salary and turning that money into bonus money. For example, if you cut Ryan's base salary to $4 million, the $5.5 million difference ($9.5M-$4M=$5.5M) would then be prorated over the remaining 5 years of his deal as $1.1M, meaning you save about $4.4 million against this year's cap.
Arthur Blank has said no "splash" free agents, so it seems like the focus of the Falcons will be re-signing players like Hawley, Peters, Babineaux, McClain, and then maybe getting whoever is left a week or two into free agency like we've steadily done the past few years.