User blog comment:AldenHeathcliffe/Chapter 551: The Burnt Offerings/@comment-10630156-20131003080937

I'd say that people who can hide their Reiatsu will appear to save Toshiro and Sui Feng. Yoruichi can do so and it has been hinted that Shunsui has seen Isshin (Soul ticket thing) who was able to hide his after his fight with the grandfisher. Alternatively the fullbrings could show up but unless they have had a major boost in power I doubt they'll do much, a Gargantua has not appeared so it is unlikely that Urahara and co are here yet. Maybe those in the soul king palace will find out about the attack and come to the fight? then there is the other captains like Ukitake, Komamura, Kenpachi etc who could turn up to give support but they are likely to be attacked by other ritters. Also there are the Visored that we haven't seen in a while. If a chop out force appears from out of no where (is already in soul society in secret) most likely it will come from the human world in my opinion.If Ichigo finds out about the attack he'll be there in a heartbeat. It could end up something like:

Isshin + ??? (Fullbrings + Ganju maybe?) vs Bazz B + Cang Du Yoruichi vs BG9

Still think that the Gotei will retreat though, to either Heuco Mundo or the Human World (Reishi concentrations do I need to say more?)