The 26-year-old, who was used in the big man role during his former club's ruck crisis when Matthew Leuenberger and Jamie Charman were cruelled by injury in recent years, said abandoning the position would ultimately prolong his career.
"My role will be pretty much the same [as at the Lions] but without the ruck. Hopefully mainly midfield, bit of forward, maybe back," he told afl.com.au in the lead up to the Suns' debut NAB Cup appearance.
"I've spoken to Bluey about not playing in the ruck anymore and he's pretty keen on that. I'm too small and light for the ruck; hopefully I never have to do that again.
"If I kept playing in the ruck, it would have cut my career short by a couple of years."
Brennan said his relationship with Lions' coach Michael Voss, despite their differing views on his rucking ability, remained strong throughout the negotiations that attempted to salvage his career with the club.
He also said he left the Lions on good terms despite the contractual sticking point that forced his decision to move on.
"I told Vossy how I felt but it just got really hard to stay there towards the end," he said.
"Contract-wise, it was almost impossible to stay.
"It was a sad time because I have a lot of friends there and walking out of the place was torture but that's football.
"Making the phone call to Vossy to tell him I was leaving was probably the toughest thing I've done because he's been good to me."
Brennan went to Melbourne to field offers from a range of clubs last October before deciding to accept the Gold Coast's offer and move 45 minutes down the highway, rather than two states away.
He said the decision was influenced heavily by what was best for his family; wife Sharai and daughters Leila (four) and Emma (two).
"I decided I wanted to keep my family in Queensland because they were pretty comfortable and the lifestyle in Melbourne, I didn't think it suited us," he said.
"That was probably the reason I didn't go to a Melbourne club, especially a big club.
"I really like the low key environment Queensland has to offer, being able to take my girls to the shopping centre and I thought it would have been a bit hard to lead a normal life."
Brennan officially moved down to the Gold Coast last month into the suburb of Hope Island, just in time for Leila to start school.
However, he continues to travel back to Brisbane "at least once a week" to visit former teammates and friends, and recently to help those he knew affected by floods.
He says he's benefited from a pre-season focused heavily on skills and he "feels younger" now he's ensconced in a group with an average age of 21.
He's also looking forward to participating in the latter stages of the NAB Cup series after ruling himself out of the Suns' first match this Saturday following his October ankle operation.
"I'll get a couple of games in the NAB Cup but I don't have enough training under my belt to play in the first week," he said.
"I'll definitely be ready for round one of the home-and-away [season]. I'm pretty fit; I'm just trying to keep up with the young guys."
Jared Brennan is a $361,300 forward/midfielder in the Toyota AFL Dream Team competition.
