The Blues lost Che Adams for a number of weeks with a hamstring injury during Saturday's 2-1 win over Bristol City.
Fellow front man Lukas Jutkiewicz is also out with a calf problem, leaving veteran Clayton Donaldson as his only attacking option.
"You haven't got to be a clever person to look at the squad and [think]: where do you go now?" Redknapp told BBC WM.
"It's a crazy situation at this stage of the season to be in."
The former Tottenham and Portsmouth boss, 70, agreed a deal to manage the club in May, having helped City stave off relegation from the Championship on the final day of last season.
"You've got no squad, you're going to end up with kids on the bench and kids playing, that's how we are," he added.
"What we need to do is to get some deals over the line. The owners and myself are ambitious. I want to see the team up at the top of the table."
Birmingham City's lack of fit, experienced strikers is a "crazy situation", says boss Harry Redknapp.