Both players are suspended with Adam serving a one-match ban after picking up five yellow cards and Demontagnac banned for three matches having been sent off during a reserve match.
However, boss Ian Holloway could decide to call upon Daniel Nardiello. The forward has returned to training after a long-term hip injury and he could be set for a place on the bench.
Neal Eardley is another injury concern after he picked up a knee injury in the draw with Swansea last week and is rated at 50/50 to be involved this weekend.
Blackpool have performed well at home but away from home they have struggled and Holloway is considering a change in tactics for the trip to South Yorkshire, meaning a move away from their attacking 4-3-3 formation.
"We have got to sort ourselves out. Our away form has to improve," he told The Gazette. "I'd like a few wins, that would really keep us up there."