I doubt that Shiryu will fight Zoro. He does not fit the portrayal of his enemies.
Zoro rarely, if ever, fought someone sneaky. Most of his opponents are upfront enemies that he will overpower after getting his ass kicked until he gets a epiphany and wins in a single hit.
The one that fights sneaky bastards without moral is actually Sanji. His enemies either change appearance, go invisible, use hostages and tricks to get the upperhand. Shiryu looks more like a Sanji enemy than Zoro's.
Of course, it would be interesting to see Zoro fighting someone without following the protocol, but I doubt that Oda will change things right at the end of One Piece.
Zoro rarely, if ever, fought someone sneaky. Most of his opponents are upfront enemies that he will overpower after getting his ass kicked until he gets a epiphany and wins in a single hit.
The one that fights sneaky bastards without moral is actually Sanji. His enemies either change appearance, go invisible, use hostages and tricks to get the upperhand. Shiryu looks more like a Sanji enemy than Zoro's.
Of course, it would be interesting to see Zoro fighting someone without following the protocol, but I doubt that Oda will change things right at the end of One Piece.