Another flip today:
4/22:
RHP Felix Paulino assigned to Lakewood BlueClaws from Williamsport Crosscutters.
LHP Ranger Suarez assigned to Williamsport Crosscutters from Lakewood BlueClaws.
It's interesting that this pitcher-shuffling by the Phils, at least, isn't confined to the lower minors. The Phillies have used the Summer-A roster (Williamsport) in lieu of a DL (or just to expand the rosters) for every minor-league club below AAA - Reading, Clearwater, Lakewood.
I don't know if there have actually been any rule changes, or whether somebody's just being more creative with existing rules about moving players (on paper). Regardless, I don't expect it to continue past the first week in June or so. It becomes more difficult to slide players on and off the Crosscutters' roster when the Crosscutters are actually playing games; if three pitchers "on the Williamsport roster" are actually cooling their heels in Lakewood, Clearwater and Reading, it makes things rather difficult for the Crosscutters' manager.
For what it's worth, perusing the NY-Penn League transactions for April, it appears that, other than the Phillies, only one organization has been making more-or-less daily use of this pitcher-flipping: the Astros (Tri-City, mostly flipping guys on and off the Fresno roster). The Mets (Brooklyn) have done a bit with their St. Lucie (High-A) roster, but there aren't routine (as in almost daily) flips as the Phils and Astros are doing.