The Bulldogs claimed the restricted free agent in the first official transaction of the free agency period that started at 9am on Friday.
The Power had three days to decide if they would match the Bulldogs’ three-year contract offer to Trengove but declined.
“Jackson has been offered a great opportunity by the Western Bulldogs,” Port list manager Jason Cripps said.
“It’s a difficult part of this industry that sometimes you have to say goodbye to great people.
“Jackson has made countless friendships at Port Adelaide that will remain strong. He’ll always be welcome back at Alberton.”
Cripps thanked Trengove for his contribution to Port Adelaide.
“Like all big men, Jackson took a little time to find his feet at the elite level, but by his second season he was a regular in AFL side and in his third year he won the John Cahill Medal as the club’s Best & Fairest,” Cripps said.
“From a football perspective he’s always done everything asked of him and more, as we saw last year when he carried the ruck load in the absence of Paddy Ryder and Matthew Lobbe.”
Trengove was the 22nd overall pick at the 2008 draft and played 153 games for the Power.
His move came as no surprise after he found himself out of favour with Port coach Ken Hinkley just before he was due to hit free agency.
The 26-year-old was dropped ahead of round 21 and was unable to earn an AFL recall.
“It was extremely hard (to leave), but towards the end of the year (the decision) was probably made for me when I was dropped,” Trengove told AFL Trade Radio.
“I was left out in a game where I thought I could help the team out.
“As hard as it was I think the timing was right to come back home.”
At 197cm, Trengove is a versatile big man who can fill several roles for the Dogs, but is likely to spend most of his time in defence.
It’s not all doom and gloom for the Power, with former Brisbane skipper Tom Rockliff poised to join the club.
The 27-year-old is also a restricted free agent, which means the Lions can match any free agency offer made to him, but he has almost certainly played his last game for the club.
Rockliff, who was stripped of the Lions captaincy last year, came close to leaving the club during the 2016 trade period.
He was heavily courted by Carlton in recent weeks but opted for Port with an eye on playing finals.
Geelong duo Daniel Menzel (unrestricted) and Steven Motlop (restricted) and North Melbourne’s Scott Thompson (restricted) are other notable players in a thin free agency crop this year.
The free agency period ends at 5pm on Sunday, October 15.
– with AAP
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