Palumbo (thumb) threw a simulated inning Thursday, Evan Grant of The Dallas Morning News reports.
Palumbo has been sidelined since Aug. 20 with a blister. This is a step in the right direction for the 24-year-old lefty, who could return to action as soon as Saturday, per Grant. If and when Palumbo returns this season, he'll likely pitch in shorter stints of one or two innings.