Hm, well Young is the only starter, so he'll probably be getting the most minutes out of the 3. Plus he just had a monster game after having 2 bad ones so hopefully he'll be solid the rest of the way.
Green has potential, especially with the bad luck Celtics are having with injuries. Problem is he's backing up Pierce who eats up a lot of minutes, so he'll probably be stuck with the minutes he has now. Unless they get ANOTHER injury, in which case he'll be a starter.
Delfino is ok if you need 3's and pts, but he doesn't excel at much else. Plus he's still recovering from his injury, probably be good to check up on him after the all star break.