David Sullivan claimed in the Birmingham Mail that had Steve Bruce not left Birmingham, they could have ended up with a bitter manager impacting negatively on the team.
The Blues co-owner said that Bruce felt "shafted" by Carson Yeung over his new contract and had become increasingly unhappy with his lot.
But he also despaired at a comparative lack of financial muscle in the transfer market, and commented to staff when he said his goodbyes at Wast Hills last Monday that he had simply "had enough."
Sullivan countered this and stressed that Bruce had been given what the club could afford.
"Because we never heard the end of it when he couldn't go to Newcastle United, had we not allowed him to talk to Wigan, it would have been fraught," said Sullivan.
"Not that we wanted him to go, but we just felt that with what they were offering Steve, and knowing how he felt here, had we blocked him the repercussions would have been unpleasant.
"We didn't want him upset and going round with a long face, creating an atmosphere, which would have fed through to the dressing room. That would have been unacceptable.
"He was unhappy as it was because he felt he had been shafted by the Chinese over his contract and we felt that to deny him Wigan wasn't right for the club."