User blog comment:GouenjiShuuya'123/The Ultimate Eleven?/@comment-4726368-20121105190026/@comment-4525039-20121107123409

That would be a massive troll for people. if Hakuryuu would suddenly appear in anime, and mix max with another out of the utimate eleven competely ignoring the game story, then what would be the point for Neppu and Raimei, they confirmed it fully that Taiyou is exclusive to Neppu and Hakuryuu to Raimei. There is no other point for Hakuryuu to appear again, until the movie.

I know Level 5 have yet to release new information, but I guess that chances Hakuryuu will appear is pretty low.

Now I also wonder when does the movie take place, Is it after they fought with El Dorado or during El Dorado,

If after El Dorado, then it possble that they were forming the New Inazuma Japan(for maybe HRI or something) using most of the utimate eleven, while doing that, they recruited Hakuryuu and Yukimura.

If it during El Dorado's battles, then they free Endou at some point and decide to have a practice match with the Inazuma Legend Japan, Yukimura and Hakuryuu also appears, but might not join the team because they felt, they were not strong enough.

Judging from what I see, I don't really know if there is a slot for Yukimura but that is just a theory

In fact this whole comment is a theory, as well as the other comments above me.