The Blues manager is concerned about how a spending spree could impact on their summer plans.
Birmingham boss Gary Rowett has admitted that he plans to take a relatively cautious approach when it comes to opening the chequebook during the January transfer window, according to the Birmingham Mail.
Already this month, the Blues have extended the James Vaughan's loan deal and have signed Sunderland winger Will Buckley on loan until February (via Mail), but Rowett insisted that he is only looking to do deals that will benefit the club in the long-term.
"I could go and sign four players now that are on loan for the rest of the season that might give us a chance of getting in the play-offs," he told the Mail.
"The problem for me, if I know I am not going to get those four next season I have got to start again in the summer and you just can't build anything of longevity with that type of mindset.
"My mindset is always, can we sign one or two on loan for impact? Can we also sign maybe two players that will give us something this season but also be even better next season?
"I could go and spend all the money I have got available now - then next season I am back to square one."
With the club just two points outside the Championship play-off places, it must be tempting for Rowett to use every resource he has available to him in an attempt to propel his side into the top six, especially considering that they watched one of the most exciting players, Demarai Gray leave the club for Leicester City earlier this month.
While the two arrivals - or extension, in Vaughan's case - that Birmingham have secured during this window may suggest that Rowett is not actually looking that far ahead, there is scope for both players to be with the club for even longer.
The Mail reports that Vaughan is a free agent at the end of the season, so would be free to join the Blues permanently, while the former Brighton's man's loan could be extended beyond next month.
That strategy may see Birmingham ultimately come up just that little bit short this season when the play-off race heats up, but it is surely the best way for Rowett to approach attempting to take the club back to the top flight, and keeping them there for a considerable period of time.