Deacon, who is now in his ninth year at with the Bulls, is the leading points score for the club, having passed Keith Mumby's record last season.
Commenting on the decision Bulls Coach Steve McNamara said: "It's a fantastic opportunity for him. I've been looking to challenge Deacs more in certain aspects of his game and this will continue to do that. He's been a fantastic servant for the Bulls – this is his ninth season now – and this is the direction I want us to head in.
Every decision I make is for the benefit of the team. I think this decision will deliberately put a little bit more responsibility on Paul and I feel he produces his best form when he is put under pressure. I believe he'll be a very, very good captain; Deacs has a lot of leadership qualities and leads by example certainly in practice and training.
Glenn Morrison joined the club from Parramatta at the end of last season and McNamara has been hugely impressed with the player
"He has impressed absolutely everybody with the overall package since he came across from Australia. Glenn is very popular with everybody and is one of the best professional people I've ever been associated with either as a player or as a coach. He's been fantastic with every aspect of what he's done from the youngest kid at the club to the top."