User blog comment:CROWMETA13/Ending of season 11/@comment-26992577-20160413125629/@comment-26992577-20160414182608

Tweeted by Rob B. https://twitter.com/RobBenedict/status/699724898952843264

The article linked in the tweet also mentioned, that he returns in ep 20.

"God may finally be answering Supernatural‘s prayers. Rob Benedict will reprise his role as Chuck — Dean and Sam’s possibly-All Powerful prophet pal — in Episode 20 of Season 11, TVLine has learned exclusively."