England Under-21 international Lees was shown a straight red card for his high tackle on midfielder Jay Tabb in Saturday's defeat at Ipswich and will start a three-game ban.
Jason Pearce is expected to step in alongside Lee Peltier at the heart of defence in Lees' absence.
Manager Neil Warnock recalled veteran midfielder Michael Brown at Ipswich in place of Rudy Austin, who had only returned from international duty with Jamaica two days earlier.
Warnock may be tempted to recall Austin to his starting line-up along with striker Ross McCormack, who returned to the substitutes' bench at Ipswich following a head injury.
Teenage midfielder Chris Dawson, an unused substitute in recent weeks, is pushing for his first senior appearance for the club as Leeds look to bounce back from successive defeats which appear to have ended their play-off hopes.