I'm playing on PS3, so I have no A button... But when I hit X, which I assume is the same thing, it brings me to the screen where I could normally, in regular season, choose between Resign, Edit, Trade, Trading block, etc... Even release. But not in post season...
As a side note, the X button is the bottom button. As far as I can tell, things are layed out the same on both... Where is the A button on XBox?