There is a 50+ page thread about closers in the Baseball Leftovers section and I'm sure they are talking about it over there.
My guess would be Soriano just because he is right handed and has done well in tight games this season, I believe he gives up most his runs when the Braves have a decent lead.
Edit: Don't count on Wickman losing his job anytime soon, unless he is injured. He is still the man in ATL.
Life is like riding an elevator. It has a lot of ups and downs and someone is always pushing your buttons.