Jason Heyward has never been the complete hitter that he was talked up as, plus he has struggled with injuries this year. It seems the team thinks he's been milking those injuries a little too much though.
Uggla is just in a bad way mentally. He'll get it straightened out eventually.
Remember, Heyward is all of 21 so he has some maturing to do. He's going to be all right, I hope.