Agree with BBR on the first held ball. Official anticipated the fould blew the whistle and signaled a foul. However quickly replayed the play in his head and realized it was a clean block and went with the held ball, which was his only out and in my opinion the right thing to do.
As for the Sheldon Williams "blocked shot" play in question that ESPN replayed "ad nauseum" the official definitely kicked it (which we do some times). A fould should have definitely been called. However, I think an argument could be made (and one the announcers never considered in their incessant babble over the play) that it was an offensive foul. Remeber Williams took a forearm to the nose. If you watch the play, the Maryland player used his off hand to fend off the defender (this contact happened first) and may have prevented Williams from getting to the top of his jump and subsequently the ball. I just throw this in as a different view point, because I don't think we as officials call this type of play enough, it happens alot and we are quick to hit the defense with a foul. All that being said, a foul one way or the other was appropriate as he did get all wrist.
BTW... isn't the wrist part of the hand, and the hand is part of the ball, so...
Just kidding!