Lopez could start in place of Carlos Rodon (shoulder) the next turn through the rotation, Daryl Van Schouwen of the Chicago Sun-Times reports.
Lopez filled in Wednesday with Rodon placed on the injured list and expected to be sidelined beyond the 10-day minimum. If manager Tony La Russa sticks with Lopez, who pitched three scoreless innings Wednesday, the start is expected to come during the three-game series against Oakland that runs from Tuesday to Thursday next week.