The son of former Collingwood and Port Adelaide player Gary Tredrea, Warren Tredrea played the bulk of his junior football as a wingman before a substantial growth spurt at the age of 16 saw him transformed into a key position player,[2] highlighted by his capture of both Port's Under-17 Coach's Trophy and the St Michael's College, Adelaide 'student athlete' award in 1995.

As an 18-year-old developing forward Tredrea found his opportunities for senior football limited, with his largely anonymous debut in Round 2 against Essendon being his sole outing for the Power in 1997.

During this time Tredrea managed 16 games for 16 goals with Port Adelaide back in the local league, ending his year on a sour note with a steady performance in the Magpies' defeat to Norwood in the 1997 SANFL Grand Final.

A simply stunning performance reaped 22 disposals, 17 marks, eight goals (a club record), three Brownlow Medal votes and an AFL Rising Star nomination.

Tredrea was rewarded for his season winning his maiden John Cahill Medal as Port Adelaide's best and fairest player and the first of four selections as All-Australian centre half forward.

The 2004 season is considered Tredrea's best year as he led Port Adelaide to its first AFL premiership in the absence of the injured captain Matthew Primus.

He booted 81 goals (career best) and took 192 marks playing in all 25 of the Power's games for the season as well as reaping a host of awards, including his fourth All-Australian centre half forward guernsey, the All-Australian vice-captaincy, his second John Cahill Medal as Port's Best and Fairest player, the AFL Coaches' Association Most Valuable Player award, the Showdown Medal, a raft of media awards and was the pre-count favourite for the Brownlow Medal,[5] only to poll a disappointing 15 votes behind the eventual winner, Chris Judd, who admitted in his acceptance speech "I thought Warren Tredrea was a shoo-in to be honest".

Tredrea repeated what he did the previous year, booting 65 goals and taking a personal best 220 marks to win his third John Cahill Medal despite narrowly losing his All-Australian mantle to Fremantle's Matthew Pavlich.

With the retirement of Primus at the end of 2005, Tredrea took over the captaincy role full-time for the 2006 season but like his predecessor, was struck down by a serious knee injury, suffering a dislocated left kneecap in a preseason game against the Brisbane Lions.

When it became obvious in Round 15 after only kicking one goal against Geelong and with the Power looking like not making the finals, Tredrea had surgery on his knee early with the intention of having him fully fit before 2007.

Prior to the occasion Port Adelaide coach Mark Williams declared, "Tredders will go down in history, certainly in his first 200 games anyway, as the best player that's ever played for the club".

Despite criticism and queries over his form for the bulk of the year, Tredrea performed admirably in season 2008, kicking 31 goals and registering 28 score assists in 17 games.

At season's end Tredrea was awarded his fourth John Cahill Medal as Port Adelaide's best and fairest player.

[26] Tredrea presented the Nine News Adelaide Weekday Sports Bulletin until being dismissed in January 2022 for not adhering to Nine Network's COVID-19 vaccination policy.