Chin Diesel said:
The early signing period is over before the 21st. So, even if he chooses UConn on the 21st us fans will have to wait for the spring for it to be official. That's terrible.
He can sign on the 19th, mail or fax his letter, and then announce on the 21st, if he so desired. The signing and the announcement don't have to be the same day. The 21st could be someone's birthday or a good day to have folks come to his high school gym, for all we know.
Or he could wait. Not like he'd have to worry about losing his scholarship.