Each team could only lose one goaltender in the expansion draft, and the Canucks were pretty thin if they had lost Kay Whitmore (who was still regarded as a decent prospect).
So they picked up Vanbiesbrouck, knowing that they would then have both McLean and one of the others.
Whitmore had been outstanding the previous season and was considered one of the best backups in the league at the time.
What's most amazing about that transaction was how little Vanbiesbrouck moved for and that he was allowed to go to an expansion team. There were some *terrible* #1 goalies around the league at that time and good teams with major goaltending problems. Cheveldae in Detroit, Beaupre in Washington, Soderstrom in Philly, Essensa in Winnipeg, Healey in NYI.
Vanbiesbrouck was 30 and dead in the middle of his prime, a former Vezina winner, and still considered a top-10 or so goalie in the league although his 1992-93 season wasn't great. And yet he was dealt for an aging #5 defender in Doug Lidster - useful player, but a pitiful return considering his talent. How on earth did some of these other teams not come up with some sort of better offer than that?
Imagine how many Cups Detroit wins if they have Vanbiesbrouck (a Detroit-born guy on top of everything else) in net instead of wasting the next 4 seasons experimenting with Cheveldae, Essensa, and a young Osgood as their #1 guys. Boggles the mind what their management was thinking.