August 12 is still listed as Wall of Fame day on the schedule. Probably was just an availability issue for him. He already has to go to upstate NY a couple of weeks prior. Or maybe there are former teammates or coaches he doesn't want to see (kidding, though if Bowa isn't there in September maybe not!). Also possible Cincinnati plans to do something.
I don't think Middleton is being self-interested here but you can bet Monty and Giles are next. It's not taking away any spots from a player at least, whereas when they've done other non-players it sometimes has. (Gillick went in with Roy but Green and Harry and Charlie and Paul Owens all got their own years).
Honestly the real answer might be that the Phillies realized they could sell more tickets this way. If the team is still in the playoff race that will be moot, but if not, would help. And alumni weekend will do well regardless.
So do we think the retired number question is settled, or might that still be a surprise?