The injury happened when he came for a ball and got a kick on his thumb during Saturday's 2-2 draw with Wolves at St. Andrew's.
The keeper had scans on the thumb on Monday and there were fears he had broken a bone.
But tests have proven there to be no break and Benno could be back between the sticks at Norwich.
However, Blues have a more than adequate replacement in Nico Vaesen should Benno be ruled out for any period of time.