Since it's mid March, I'm not really concerned whether CB Tramon Williams is at voluntary workouts or S Nick Collins is at home with his family.
I'd actually be shocked if Collins was in Green Bay while his was at home expecting the birth of their third child. If I told my wife that I had to leave Florida for Wisconsin to spend some time in the gym with my teammates, and possibly miss the birth of our third child, she would kill me. Team is important, but staying alive is even more important.
I've written about Williams before. He doesn't have any leverage right now. Although RB Ryan Grant was an exclusive rights free agent last season and was able to negotiate a new long term deal, Williams is no Grant. He's got to work hard now and wait for restricted free agency.
If these two play in 2009 like they did in 2008, it doesn't matter if they're restricted or unrestricted free agents. As restricted free agents in an uncapped year, some team(s) will go hard after these them and offer more than they are currently asking for. The Packers should be negotiating with both of them now so they never come anywhere near free agency.
Short of a Jay Cutler type meltdown from either of them, I don't think Bus Cook is representing either Collins or Williams, they both are playing in Green Bay in 2009. They aren't going anywhere. This is something that can be worked out any time over the next few months.