Carlton’s captaincy candidates are likely to battle for the coveted role during the NAB Cup.

Coach Mick Malthouse wants to trial several players on game day during the pre-season competition before making a decision on who will replace Chris Judd.

Defender Nick Duigan, the only new member in the Blues' five-man leadership group, said on Wednesday morning he was unsure if the decision would be Malthouse's alone or whether it would go to a vote.

"He wants to get a better read of the players, wants to see how captaincy might impact on them, see how we handle it maybe on game day, so that'll be through the NAB Cup period," he said. 

"And I think possibly towards the end of that period Mick and the group will sit down and nut out a leader."

Duigan confirmed the three main candidates for the role were Marc Murphy, Andrew Carrazzo and Kade Simpson, each of whom he said was "well and truly capable" of doing the job justice.

"Carrazzo and Simpson are quite different leaders," he said.

"Carrazzo is really demanding and vocal and a more extroverted leader within in the group, certainly off-field in terms of setting standards and training standards and professionalism with bike sessions and rehab and hydro and all that kind of stuff.

"Simpson does all of those things as well but is maybe not as outspoken and loud as Carrazzo and prefers to have his on-field leadership do most of the talking. 

"He's certainly a really courageous player and always likes to play the team role as a winger, making sure he's picking up the loose player."

Of Murphy's chances, Duigan said "it doesn’t hurt that he's one of the best players in the country.

"The last two years I've been here I've seen him really grow into leadership material," he said. 

"He's really demanding of himself and that just rubs off on all the players he's around."

Duigan agreed the Blues would miss Judd as captain, but said it would give other players a chance to step up to fill the void. 

He said the superstar's position within the team wouldn't change greatly apart from his official title, his role in meetings and as a public face of the club. "The way he goes about it around the club will be the same," he said.

Duigan said rising to the leadership group was part of his plan to get the best out of himself.

It marks a remarkable rise for the defender, who two years ago was playing for SANFL club Norwood. At the age of 26 he was selected with pick 70 in the 2010 NAB AFL Draft, and has since played 38 AFL games.

The Blues' system requires players to nominate themselves for a leadership role and then state their case to their teammates before it goes to a vote.

"I just said that if they voted me in they could expect from me next year the same as what they've seen from me the last couple of years," he said. "I've just tried to earn respect from the playing group by working really hard and being professional and having a crack on game day."

He said his case for promotion was helped by being one of the Blues' older players, along with his previous experience as a member of the leadership group at Norwood.

"Obviously (it's) a different club, but a lot of the same sorts of things go on in all different footy clubs around Australia," he said.