User blog comment:ArtDraw12/TD Theories: Who May Return in Potential Future Seasons?/@comment-2212492-20160617085157

And therefore, the reason for B's silence according to the show is because he was a last-minute addition and by this point, ROTI had been recorded. He was added around the time that the season had been delayed due to radioactivity becoming an issue in Japan.

There are no plans for him other than being a silent character that can be used for gags.