Allardyce lost Stephen Carr and then replacement Peter Ramage during yesterday's 2-2 draw at Middlesbrough.
Allardyce said: "That, on top of not winning today, makes me feel like we have lost rather than drawn.
"We will have to deal with those injury situations tomorrow and see whether that takes us into the market on a more ferocious basis this week, which it might have to.
"I am well short now defensively, which is where my biggest problems have laid all summer.
"They are back there again now because of two injuries. It is typical, you always seem to get injuries where you are short.
"We are short in that area and we picked up not just one, but two injuries, and certainly one looks quite serious.
"With the window shutting, we will have to have a good look around and see how we go on."