It's official. He will indeed be out for this game.
Honestly, while I'm not one of those who thinks it actually helps us in this game (those who look at our final 5-10 minutes against Arky, when we went small), I don't think it necessarily hurts us. If we had to lose one player this tournament, I would pick Meeks, not because he's a bad player, but because he's relatively slow and unathletic. I don't think his absence hurts too much. The only way it becomes an issue is if our other big men get in foul trouble/foul out. Hopefully that won't be the case.