Tredrea, 29, led the Power in a club record 96 AFL games and stood on the premiership dais in 2004 in the absence of injured skipper Matthew Primus.
The four-time All-Australian will step down from the club's leadership group, but said he would still act as a mentor for the Power's new captain.
"It [stepping down] is not a decision I've taken lightly. It's something I've been discussing with family and friends quietly over the past couple of months and went to Mark [Williams] about a month ago, in the break, and told him of my wishes," Tredrea said on Tuesday.
"As a Port Adelaide boy from day one, it's been a dream, an honour and something I'll always cherish throughout life, but I think there's an opportunity now for me to pass on to the next phase.
"We've got a lot of younger guys who are definitely waiting in the wings for the opportunity to captain the club and I want to be around so I can help them in their early stages.
"It's definitely not a situation where I'll step back and leave the club's leadership program full-stop. My choice is to step out of the leadership group but to more or less act as a mentor the incoming leader, captain or captains, whichever way we decide to go in the future."
Tredrea, who has been involved in the Power's leadership group since 2000, said a need to focus more attention on his personal preparation was a reason behind his decision.
"The commitment of being an AFL captain is huge and it's probably something the general punters don't understand," he said.
"There's a lot of extra stuff that's involved in terms of the meetings and the commercial commitments as the captain and spokesperson of the playing group, and I want to take that focus and put it into myself for the last few years.
"There have probably been a number of players who have gone that way like James Hird, Shane Crawford and Chris Grant over the years. I want to be around to help that next captain and also use that five or 10 per cent of energy [into my own game].
"As I get older it is getting tougher and [I want to] to put those energies into best preparing myself, so I can play better for the football club."
Tredrea's replacement could come from any number of players in the club's 2008 leadership group.
Shaun Burgoyne filled the role of acting skipper last season when Tredrea succumbed to a shoulder injury, while Kane Cornes and Dom Cassisi took huge strides in their leadership development.
Brendon Lade and Chad Cornes were also vice-captains alongside Burgoyne.
The playing group will vote on a new leadership group in the coming days with the captain expected to be announced before Christmas.
"There are a couple of guys who have really come a long way in their leadership and you don't have to be Einstein to work out who they are," Tredrea said.
"There are probably four or five guys who I think are a genuine chance to become captain and that will happen over the next four, five or six weeks."
