Former Birmingham manager Gary Rowett has revealed that the Blues passed up on an offer to sign Manchester United's Victor Lindelof because he didn't seem strong enough a player at the time.
The Swedish defender, who completed a £39.5m move to Old Trafford over the summer, is yet to establish himself as a regular under Jose Mourinho.
"We had a look at him (Lindelof) and put it to some of the staff, but it was ironic because they felt he wasn't probably quite tough enough.
"Then suddenly he's been touted around at £20m or £30m. So I think we made a mistake.
Lindelof, 23, did not make the bench for United in three of their four Premier League matches this season, but played the full 90 minutes in a win against Basel in the Champions League, also starting against Burton in this week's Carabao Cup tie.