User blog comment:Omega natsu2/Episode 177: The Eclipse Plan, Review./@comment-189.220.21.245-20140412195242/@comment-7418318-20140412202238

That he doesn't participate due to his magic being drained is just what Datong thought.

In truth he doesn't participate, because Natsu, Mirajane, Wendy and the three Exceed are trying to break Lucy out of prison, as can be seen by that last scene where those characters are running toward Mercurius.