Grant's orders to Thomas on the night before were:
I have instructed General Sherman to advance as soon as it is light in the morning, and your attack, which will be simultaneous, will be in co-operation. Your command will either carry the rifle-pits and ridge directly in front of them or move to the left, as the presence of the enemy may require.
The only part that failed was that Thomas should "
be simultaneous" . Thomas dragged his feet waiting for Hooker, leaving Sherman without the promised cooperation.