Since he supposedly isn't hiring an agent is it possible that he could announce today and then return later?
Possible if that is the case but unlikely. When the NCAA pushed up the ultimate decision date to early April they knew what they were doing.
When the date was much later these kids could participate in various pre-draft camps and get a feel on where/if they would be drafted. Now they simply do not have that choice anymore. Because by the time those camps come about the decision date will have long since passed.
That is why it would take a real change of heart between now and April 10th for him to back out.