Adams subsequently signed a new five-year deal with the Blues, and Redknapp insists that the youngster was always destined to stay at St Andrew's.
"We turned down £10m for Che on the transfer deadline," he told talkSPORT. "If it's not public who it's from I wouldn't want to talk about that, but we did have a bid of that figure. We didn't want to sell him.
"We are building a team here, the owners are ambitious for this club. They are looking to build a team going forward that can get in the Premier League, that's the ambition of the club, that's my ambition, to take this club into the Premier League.
"Che has to buy into that as well. It is a good club and if he can help take us to where we want to go that's fantastic. It was a great offer but we are not a selling club. Birmingham now, with the owners, are not a selling club.
"They want to keep good players and build a squad around the good young players and build a team - it was never an option to sell him."
Adams joined Birmingham from Sheffield United last summer and went on to score seven goals in 42 appearances in his debut campaign.