Birmingham rejected the opportunity to sign Manchester United defender Victor Lindelof while he was at Benfica as he was not "tough enough," according to former manager Gary Rowett.
Lindelof, 23, joined United from Benfica during the summer for a reported £30.75 million, though he has yet to secure a regular starting spot under Jose Mourinho and is still awaiting his Premier League debut.
According to Rowett, who currently manages Derby, Championship club Birmingham opted against signing him -- although he accepts they made a mistake.
"About two or three years ago when we first went into Birmingham an agent called us and said we are trying to get some of our younger players out to expose them to different levels," Rowett told Sky Sports.
"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.
"To be fair he got straight back in the Benfica side very quickly and of course went from strength to strength."