Speaking at the NAB AFL Draft Camp, Harvey said Fremantle wanted a higher pick in exchange for Warnock.
"Robbie is in his fourth year as a league ruckman and he is a terrific kid and he's got a lot of things going for him, particularly his age," Harvey told afl.com.au.
"So we're looking for something below [pick No.24]."
Harvey said Freo had a couple of trades to resolve, including the Warnock deal and midfielder Josh Carr’s request to move back to Port Adelaide.
“We won't be doing anything with our early picks, so we'll just try and do the best deal we can for our football club," Harvey said.
"In respect to Robbie and Josh's decision to move on, then we'll look for that best deal. It becomes interesting, particularly with Robbie, because of his age and ability.
"Hopefully, we can get Robbie solved early in the week, but I'm not sure if that will happen. We'll speak to Port Adelaide about Josh during trade week and we'll just see what takes place from there."
Harvey estimates Fremantle will have 8-10 selections in November’s NAB AFL Draft.
"We're going to be very active in this draft coming up and we think there is a lot of good quality kids, so hopefully we'll come up with the right kids," he said.
With several Fremantle players now retired, the three-time Essendon premiership player said exciting times are ahead for him and the club to put their stamp on a new list.
"We basically made a decision that we're going to put together a plan of younger players [developing] together – first, second and third year players – and hopefully in time, we can fast-track a lot of these kids," Harvey said.
"Hopefully they'll get a real bond and resolve amongst them and they'll play as a team and be demanding on each other. You see what has happened with sides like Hawthorn and Geelong, who have played in grand finals and a lot of them have come through together.
"We've got some real leadership to surround these kids around, with the likes of [Matthew] Pavlich, [Aaron] Sandilands and [Luke] McPharlin, plus the likes of Des Headland and Paul Hasleby, who we didn't have this year (because of injury).
"So it becomes intriguing for us and if we get the dynamics right, then hopefully we won't see necessarily the frustration of … like we did this year, losing a lot of games by small margins."
