Darvish (back) threw a bullpen session Friday, AJ Cassavell of MLB.com reports.
Darvish played catch Tuesday and was able to resume mound work Friday. The right-hander has been on the injured list since Aug. 15 due to lower-back tightness, but he's eligible to return during the team's upcoming series against the Dodgers, which begins Aug. 24. Darvish is certainly progressing well in his recovery, but his return timetable depends on how he feels following Friday's throwing session.