Diekman (abdomen) will make his second minor-league rehab appearance Wednesday with Double-A Frisco, Jeff Wilson of the Fort Worth Star-Telegram reports.
Diekman made his first appearance of the season Thursday, striking out two in a clean scoreless frame. The 30-year-old will likely make one or two more rehab appearances following his Wednesday action, but could conceivably return from the disabled list in the next couple of weeks.