Robertson was suspended by A&E over anti-gay remarks he made in a GQ profile. The duck hunter- turned-reality TV star compared homosexuality to bestiality, among other things.
Sheen, who has seen his own share of controversies, ripped into Robertson in a lengthy Twitter rant. Sheen called Robertson "mallard brained" and said his comments were unforgivable.
"The only 'Dynasty' you are attached to might be the re-runs of that dated show," Sheen said in part of the tirade. "Shame on you. You're the only surviving brain donor I've ever known."
Meanwhile, Entertainment Weekly reports that A&E will resume airing new episodes of "Duck Dynasty" on Jan. 15. Those episodes will remain intact and feature Phil Robertson.