Yikes, that sucks. I hope he recovers well and comes back strong after surgery.
I don't think this is a "fork sticking" blow though. If you thought Rondo was, I can understand that. While Sullinger was a great rebounder for us, he was 9th on our team in minutes per game. He's not a "crucial" player. For me, I'm more concerned about his long term rehab.
I'm still optimistic about this year. By no means are we favorites, but I think we've still got a puncher's chance. I think that this injury is going to provide more consistent minutes for Bass, similar to what he got last season, and I think we're going to see his production rise back up to the level he played at last season. It will also provide some more minutes for Jeff Green and we'll get to see what he can do with those.
Let's see how it turns out!