Blake Ferguson has agreed to terms for a three year deal with the Parramatta Eels starting in 2019.
"I had a conversation with him about how important it is for us that we want the right people and good people at our club," Arthur told NRL.com after Ferguson's signing was announced.
"We're going through a period where we want to make sure that everything we do on the field and off the field is professional and meets the standards and expectations required by our club.
"He's fully aware of his responsibilities and accountability to his teammates and the club and he wants to be one of the players that can lead that."
Ferguson has run for almost 400 metres more than any other player in the competition and scored 10 tries from 15 games.
Arthur has not guaranteed him a concrete position in their backline, with Ferguson able to play wing, centre and fullback.
"We'll have to wait and see [where Ferguson plays in 2019], but he's going to help us out of the backfield," Arthur said.
"He can play centre, he can play wing. He's a big body and he's probably the form outside back in the comp at the moment.
"He's a quality finisher and is good at getting sets started out of the backfield."
The Club looks forward to Blake joining the Blue and Gold for the start of the pre-season in November.