The Mirror says Birmingham supremo David Sullivan last night threatened to put Black on gardening leave to stop the Scot walking out on City.
Blues have given boss Bruce, 46, in charge at St Andrews since December 2001, permission to speak to their Premier League rivals about becoming their new manager after accepting a huge compensation package.
And Bruce is set to be unveiled at the JJB Stadium next week on a bumper four-year deal worth around £2million a year when Latics owner Dave Whelan returns from his Barbados holiday home. But Birmingham's hierarchy, who met at Sullivan's Essex mansion yesterday, are determined to hang on to Black as they want him to be their caretaker boss.
Former Coventry manager Black, 44, who is on a 12-month rolling contract, is a vital cog at the club.
He is tactically astute and can speak to Birmingham's foreign stars in several languages.
And Birmingham know without the highly-rated coach they will find it very difficult to attract a capable replacement while there is so much uncertainty surrounding the club due to Carson Yeung's protracted takeover.