I want to really see Castle play too, but only if he is 100% ready. I don't want them risking anything this early on if he's not.
It's just a bit frustrating, as I've really hated the Spurs not being able to incorporate all their main players in the pre-season so they can get used to playing together. The past couple of seasons, I feel they've started off on the back foot, and for a young team trying to make the playoffs, that doesn't help them going into the season. These days IMO, the preseason is more important that it used to be.
When we had TD, TP, Manu, it didn't matter much as they could play prospects looking to make the team and lose all the games without the main guys playing much, but now, I think it's more important the regular rotation guys play together as much as they can to build chemistry and cohesion against NBA competition. I don't think workouts and playing against each other in practice fully simulate that.