Diekman (abdomen) threw live batting practice Wednesday, Stefan Stevenson of the Fort Worth Star-Telegram reports.
Diekman said he felt good afterwards, so he'll toss another live session this Saturday before likely heading out on a minor-league rehab assignment. The 30-year-old remains without a firm timetable for his return from the 60-day disabled list, but mid-to-late August seems to be a reasonable estimate given his recent progress.