And acquit themselves pretty well while pitching for rookie-league Bradenton: Patel pitched a 1-2-3 inning with a strikeout, and Singh allowed one run and had one strikeout in an inning.
These guys' situation is obviously extremely unusual, so it's easy to see why the Pirates have mostly treated them as a unit--signing both of them, assigning them to the same team, and so on. Reading their still-excellent blog, it's clear that they both benefit from having the other around. There might also be some sort of public-relations benefit to having them both make their debuts in the same game. But from now on, it might be nice, if they're ever going to be pitchers rather than mere curiosities, for them to have separate careers. Hopefully they won't necessarily pitch on the same day from now on.