GEELONG premiership ruckman Trent West says he was "shocked" at how quickly his time at the Cats came to an end.

West yesterday revealed he only became aware of a potential trade to Brisbane two nights before the end of the three-week trade period.

The 26-year-old, who was contracted for next season at Geelong, was won over by a three-year deal to join the Lions, where he will assume the back-up role to first-choice ruckman Matthew Leuenberger.

In return, the Cats got pick 41 in the upcoming national draft.

"It was pretty late. I was away and (manager) Anthony (McConville) called me and said 'Brisbane are pretty keen,' so we went from there. I had to make a decision real quick," West told SEN.

"I was pretty shocked. I didn't know what to say, really. I was trying to be excited, but I wasn't really at the time.

"I could have stayed at Geelong, no worries, but I had to weigh everything up and do what was best for me."

West was on a remote island off the Northern Territory when word of Brisbane's interest filtered through.

He was up there as part of a community trip with the Cats and was alongside some of his closest mates, making the sudden change of clubs an even more challenging situation for him to come to grips with.

"One of my really good mates was there. It's always hard to talk about that stuff with your teammates but it had to happen and we got through it," West said.

West said it was hard to leave the Cats.

"I guess I am (shattered)," West said.

"But I can't sit there and think 'I wanted to be a one-club player,' it's not the way it is now, and I've got to be really optimistic about the move up there. And that's what I am."

West, who played in the Cats' 2011 flag-winning final and shouldered the main ruck role until midway through this year, will receive greater senior opportunities at the Lions.

He said the trade happened so quickly that he was a Lions player before even chatting with Brisbane coach Justin Leppitsch.