Espinoza's agent, Barry Silkman, as allegedly told The Sun newspaper that Blues' co-owner David Sullivan had cemented the deal for the Ecuardorian international after McLeish had snubbed the chance to sign the 32-year-old centre-back.
"The board have given me great backing so far, so I'm dismayed by claims in today's paper suggesting I'm not happy with the signing of Espinoza," McLeish has said.
"The Espinoza deal made good financial sense for the club and although he's a rookie in English terms, he has vast international experience and it will be up to the centre-backs to compete as I attempt to build a solid spine.
"There are absolutely no problems with the board. I'm happy with all the signings and happy with the support I've had from them, and to suggest otherwise is ridiculous.
"I'm also thankful that the board have indicated they'll support me further before the season begins as we build the club for the Premier League."