I wanted to add a further thought here.
16 of the 31 kids signed from the draft and UDFAs have been placed on rosters. 15 have not, as of yet.
It's not just a matter of deciding which roster (FCL, Low-A) is appropriate. The organization also has to make roster space — which means they have to make decisions about which current players get released.
Since July 1, the Phils have released 13 minor-league players (if I counted correctly), and traded 5 more. But to place 15 more kids on rosters, they're going to have to move some more people out — and decisions as to who to release (or trade/sell) presumably don't all get made at the same time, so this becomes a factor in how rapidly the remaining guys get assigned to rosters... along with the completion of whatever preliminary evaluations are going on at the Complex
The club moved seven guys en masse to the FCL roster this morning — the first such placements (excluding two guy who went directly to the "full season IL). If I had to guess, I'd look for some similar kind of relatively large batch of assignments to Clearwater — coupled with movements (releases, reassignments upward) of some players currently on the Clearwater roster, within the next couple of days.