The Scot, outstanding in the Owls’ shock 3-0 slaying of Arsenal in the previous round at Hillsborough, has not recovered from a knee problem and is one of seven players out for tomorrow’s test in the Potteries.
Defender Michael Turner is still missing with a knee injury, but he and Bannan could return for Sunday’s Championship game with high-flying visitors Derby County.
Goaleeper Keiren Westwood (Achilles) is also out, with Carvalhal sticking with his policy of employing Joe Wildsmith in goal in the Capital One Cup, in any case.
Loan striker Gary Hooper is eligible, having not played in this season’s competition for parent club Norwich City, but Fernando Forestieri cannot play, having played for Watford already in round two.
Marco Matias, Vincent Sasso and Sergiu Bus are also missing for the Owls.
On Bannan, Carvalhal said: “He is better, but not fit yet and he is in no condition to play like Turner.
“We expect them possibly for the next game (Derby), but you never know because of the nature of the player.”