The White Sox remain hopeful that they will be able to add one of their strongest bullpen weapons to their postseason roster, and they were encouraged by the on-field activity on Saturday that indicated there was progress on that front.

Left-handed reliever Aaron Bummer threw a 20-pitch simulated game at Great American Ball Park in Cincinnati, prior to the Sox game with the Reds. Bummer has been sidelined since early August with a left biceps strain and a nerve issue near the muscle that developed after the initial diagnosis.

"He looked good -- really, really good," manager Rick Renteria said of the simulated game. "He says he feels good, so we're very positive about how he's progressing."

Adding Bummer to the bullpen mix would be a big lift for the White Sox as they prepare to play in their first postseason game in 12 years. At the time of his injury, Bummer was arguably the Sox most valuable pitcher. He posted a 1.23 ERA over seven games, was one of the best in baseball at inducing ground balls and had sterling success against left-handed hitters.

The injury cut short what looked to be a continuation of a stellar 2019, during which Bummer posted a 2.13 ERA and 0.99 WHIP over 58 games, spanning 67 2/3 innings.

Bummer is one of two rehabbing lefties the Sox are hoping will be able to contribute in October. Carlos Rodón, who's been sidelined since Aug. 4 with shoulder soreness and back pain, is also progressing well in his comeback efforts.