Rodon threw a fourth simulated game Monday, Dan Hayes of CSN Chicago reports.
Rodon, who started throwing off a mound earlier this month, threw 60 pitches and got up and down four times Monday. It was another sign of his pending return, though the White Sox refuse to put any timeline on the left-hander. General manager Rick Hahn said the next step for Rodon is to build up arm strength and endurance.