We can't just release someone because we fancy it. This isn't Football Manager. The club will have tried to work something out between Carson and Gardyne, clearly it hasn't worked, maybe something else has happened behind the scenes that we aren't aware of and as a result the club have decided to move one of them on. Getting an agreement that works for all parties won't happen overnight, especially if one of the parties doesn't agree to what is being proposed, so perhaps it's not that surprising that it hasn't happened quickly.
Anyway, it's done now and we now need to take whatever monies may be left in the budget and seek to improve the squad as our rivals are already getting reinforcements in for their own title / promotion pushes.