The Dogs, having lacked a power forward in recent times, could have targeted Thompson after the Kangaroos this week reneged on their decision to allow the 30-year-old to play on in 2009.
But assistant coach Leon Cameron said his side would be more interested in a longer-term prospect than the former Hawk and Roo.
"You can't just keep going down that track of having one year here, one year there," he told SEN on Saturday morning.
"If you're talking about a key forward, you've got to go all out."
Cameron said the recruitment of such a forward would be on the agenda this week when the Dogs begin the post-mortem on their season.
"We meet first thing Monday morning. We'll let the dust settle this weekend and then meet and assess it all next week," he said.
"We have player interviews and assess the list. You keep assessing it during the year as well, but we'll make some calls sometime next week on some players and what we need.
"What do we need? We would love a big key forward.
"It's a priority, but it's a game where you've got to give up to get it.
"You look at it and say, 'Who do you give up?', but it's about what's out there as well,"
"There's probably three or four key forwards out there and they've all re-signed.
"Do you then go to the second or third stringers? They're the decisions we'll make next week."
He also said the Dogs remained optimistic 2007 No.5 draft pick Jarrad Grant would develop into such a player, after his debut season was ruined by the early onset of osteitis pubis.
"He's a young kid who we hope will play a dozen games next year," he said.
"He's come along in terms of his physicality in the gym really well, but again, for consistent football, he's two to three years away."
Cameron also defended the Dogs' decision to play Adam Cooney on Friday night in their losing preliminary final after it was revealed the on-baller has been battling a knee problem.
"It's the risk you take, but if we had our time over, then no [he wouldn't have missed]. Adam Cooney is a quality player and yes, he has been restricted a little bit, but they've got to put a good quality player on him as well," he said.
"If he's not there, then all of a sudden, they just target Ryan Griffen."
Cooney will have scans this week to find out if his kneecap is cracked.
