Both loan signing's Jerel Ifil and James Milner are not able to play as Watford and Leeds do not want them to be cup tied.
Andy King will also rest top scorer Tommy Mooney who picked up a slight injury at the game with Barnsley, but Mooney should be back in the squad for Saturday's home game with Peterborough.
Swindon have so far sold around 2,500 tickets for Wednesday night's trip, and as of last week Leeds had sold over 20,000 tickets for the game, so it's likely to be the biggest attendance of the season that Swindon will be playing in front.