I'm letting the bird go. I'm putting him in a little box with some grass up in the tree I found him under. I feel a little bad for leaving him but his parents might find him since they should be awake soon. Thanks for the advice, everyone.
Here's a little update. I just went and checked on my makeshift nest I made for the bird in the tree down the street where it was found. He wasn't in it, but there was some poo. There were no bird remains nearby so I hope he's doing alright.
His parents probably got him out. He has some feathers and may have tried to mimic his parents and fly too early.
My family gets TONS of bird nests around our house since we feed birds with a feeder and have caged birds (oddly it attracts wild birds - and domestic birds that have gotten out and recognize food and safety of cages). So we get a lot of fledglings around on the ground. The best thing is to see if you see their parents around (some birds like mocking birds have only a couple at a time and they'll be watching). Let the parent birds see where you place the bird. Put it in a bush, tree, on the roof, etc. High enough to be safe from predators. Then leave it be. It ISN'T true that parent birds won't touch the baby after a person touches it - thats just an old wives tale. You can check on the baby later to make sure its ok, but chances are the parents found it.
If yours isn't in its box anymore than the mommy and daddy found it and moved it to hide it their way. My money is on him being fine and happy with his parents.
(info from vets/bird rehabilitators - we've had our share of taking them to sanctuaries etc. and have gotten the info from professionals. My parents love birds - I'm not a big fan - they're noisy. But they are cute as babies).