White Sox's Aaron Bummer: Not throwing yet

White Sox manager Rick Renteria said Tuesday that Bummer's biceps is "loosening up," but the lefty has yet to begin a throwing program, Scott Merkin of MLB.com reports.

The White Sox have been encouraged with how Bummer has bounced back from the left biceps strain after landing on the 10-day injured list Saturday, but a target date for his return probably won't be established until he's cleared to resume mound work. Before getting shut down with the injury, Bummer had served as Chicago's top setup man, giving up one earned run on four hits and four walks over 7.1 innings while striking out 12 and collecting three holds.