I could see an argument for him needing to be on the 40 man for that 15 day period. I mean, he is a Rule 5 pick after all.
I assume we do agree he would have to be added after those days expire, however the rules get interpreted here. Their current roster is full per the Phillies’ own website (which I can’t guarantee is current, but still is the best source). But it also has Harper still on it, and we know he’s definitely out until July/August.
I imagine they’d just IL Harper and then add him. Maybe they’re waiting until he pitches a few times to make that call about adding him or just returning him for a full refund…