Kalil suffered an ankle injury during the Week 7 victory over the Philadelphia Eagles and did not practice all week. Thompson suffered a knee injury during the Week 6 victory over the Seattle Seahawks and has not practiced since.
"It'll be game-time decisions," head coach Ron Rivera said.
Guard Fernando Velasco, a seven-year veteran who served as the primary center for the Steelers in 2013 and the Titans in 2012, will step in for Kalil if needed. Rivera said he feels "very comfortable" with Velasco after a solid week of practice.
Defensive linemen Mario Addison (shoulder) and Dwan Edwards (ankle) also did not practice all week and have already been ruled out.
Rookie offensive tackle Daryl Williams is probable and set to return to action for the first time since suffering a knee injury in the season opener. Rivera hopes to give Williams "a series or two" and said he'll serve as the primary backup at tackle.