"She buggered that club. Central to your role when you're the general manager of a club, is salary cap. That's your first, first and first priority."
Leckie's comments come a day after rugby Australia announced the signing of Kiwi Dave Rennie as the next Wallabies coach, following the departure of Michael Cheika after the Rugby World Cup.
Cheika stood down from his post as Wallabies coach after five rough seasons in which the Wallabies won just 34 of his 68 games in charge.
Speaking to Radio Sport's D'Arcy Waldegrave on Wednesday, Castle said Rennie's signing was an exciting one for the organization.
"He was by far and away the most outstanding candidate," Castle said.
"We believed he was the best fit not only from a performance coaching point of view but also a cultural point of view and his experience in bringing groups of people together is very sound.
"Dave's proven ability both at the Chiefs and what he's done in a short time with the Glasgow Warriors to bring together a group of men and build a culture where they all want to work together toward the same thing is one of his best skill sets and that's something we know will be very valuable to us.
"We had a plan and we worked really hard to execute it."