Birmingham have completed the signing of Blackburn Rovers defender Martin Taylor in a three-and-a-half year deal worth £1.25m.
But boss Steve Bruce said they must wait until the summer to try and sign Manchester United's Nicky Butt.
Bruce believes he has acquired "a huge talent" in capturing 24-year-old Taylor from Blackburn.
"I'm delighted to have got Martin and it would have been nice if Butt came to the club now as well," said Bruce.
"But the plan throughout was always to try and keep most of the money for the summer when more players are available.
"At this juncture people are reluctant to sell the kind of quality players you are looking for in general.
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Martin meets the criteria of what I'm trying to get into the club
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Blues boss Steve Bruce
"Martin Taylor appeals to me because he is versatile and young, he's English, he is six feet, four inches tall and he can play right-back, left-back and centre-back.
"He is very comfortable on the ball and I think he is an outstanding talent.
"I believe that if he gets confident, then we have got a genuine, huge talent on our hands.
"There are not many footballing centre-backs or full-backs like him. He has quite incredible balance for someone so big.
"He is someone that I've watched and checked a lot and he meets the criteria of what I'm trying to get into the club."
Birmingham are currently without injured defenders Stan Laziridis, Matthew Upson and Jamie Clapham.
The 27-year-old was way down the pecking order at St Andrews and is expected to join Los Angeles Galaxy.