For S&T, Giddens makes slightly more money, plays SG, Walker SF. Likely Ainge wants to keep Giddens for SG and use Daniels for SG/SF swingman. Also, could be that Danny's going to want to sign Swift for more money than veterans minimum and might want to sign Tim Thomas (vet minimum). Last year, Lue wouldn't take the veteran minimum so he likely won't again this time and neither will Starbury. So, guess is that Danny's trying to move positional players and shape the roster.
Who knows if Baby will be coming back or someone else in a S&T. S&T may yield a SF or PG, leaving Danny with no home for Walker. My guess is Danny's trying to work out a S&T to get Swift and that may take multiple teams. Remember that one trade a few years back when 5 teams completed a S&T with Walker going to Miami?