The fourth round replay at Victoria Park ended goalless before United won through 4-3 on penalties.
Banks, who will be 39 next month, was only told he was playing the day before the game after regular number one Dusan Pernis picked up an injury.
Banks said: "Dusan is struggling a bit with a thigh injury, it was a precautionary measure to rest him.
"We didn't want him to kick a ball, hopefully he will be fit for Saturday.
"I'm here as back up and to coach the keepers, but I thoroughly enjoyed playing, I can't honestly remember the last time I played a competitive 90 minutes."