With Chris Judd stepping down last year after five seasons as skipper, the Blues playing group voted to include Duigan, Jarrad Waite, Marc Murphy, Andrew Carrazzo and Kade Simpson in a five-man leadership squad.
Malthouse will make the final call on the captain before their opening-round clash with Richmond.
Duigan, 28, will lead Carlton in their NAB Cup meeting with premiers the Sydney Swans on Sunday.
Duigan has impressed in 38 games for Carlton since being plucked from the SANFL two years ago.
He was elevated to the leadership group on the club's recent pre-season trip to Arizona.
"It will come from one of those five blokes," Malthouse said on Thursday.
"Each one has equal grounds to take over the captaincy."
Malthouse has a history of left-field choices to be his leader, handing the mantle to an unheralded Nick Maxwell when he was coach at Collingwood.
He also backed rugged defender John Worsfold as West Coast skipper, a role he held for eight years.
Maxwell and Worsfold both led their teams to premierships under Malthouse's tutelage.
"The best players don't necessarily make the best captains," Malthouse said.
"It would be fair to say that five years ago no-one picked Nick Maxwell and he's still there, so there so he must be doing something right.
"And Nick's far from the best player."
Murphy will captain Carlton in its opening game against Greater Western Sydney at Blacktown on Sunday, while fellow candidates Carrazzo, Simpson and Waite will get their turns in later matches.
