Westburg (elbow) will begin a throwing progression this week, Jake Rill of MLB.com reports.
It's a major step for the infielder, but there remains no timetable for Westburg's return from a right UCL sprain. He is already on the 60-day injured list and thus not eligible for activation until late May. Coby Mayo has been filling in as the Orioles' third baseman and will continue to do so while Westburg is shelved.