Brubaker (shoulder) recently threw off flat ground from 90 feet, Mike Persak of the Pittsburgh Post-Gazette reports.
Brubaker began a plyometric training program last week, and he's now in the midst of a throwing program. Pirates director of sports medicine Todd Tomczyk isn't sure whether the right-hander will have enough time to return during the regular season, but a better idea of his status should be revealed based on when he resumes mound work.