Smith hasn't practiced since spraining his left ankle in Sunday's loss to New Orleans and has been in a protective boot this week. Martin has been sidelined since sustaining a concussion against the Saints.
Linebacker Jamar Williams and right tackle Jeff Otah also won't play Sunday against the Bears. Williams has a neck injury and Otah hasn't played or practiced all season because of a knee problem.
Running back DeAngelo Williams practiced for the second straight day Friday following an illness and is probable for Sunday. Cornerback Captain Munnerlyn practiced and is probable despite a sore foot.