Blackwell said: "We have to try and get in another goalkeeper. The situation is desperate and we'll see what happens. Bennett is out for another three weeks and the deadline for signing closes on Thursday.
"The problem is that if anything happens to Bunn we don't have another goalkeeper, plus we have possibly five games to play before Bennett will be back.
"I had to hold my breath when Bunn went down in a heavy clash (at the weekend) because we have no-one else. It's proving difficult to get a player of the calibre who fits the bill, but we have to try."