Smith (shoulder) threw a bullpen session Tuesday, MLB.com reports.
Smith is working his way through a throwing progression after being placed on the 15-day injured list May 22 due to right shoulder inflammation. He'll likely need to complete another side session or two before advancing to facing live hitters and then heading out on a rehab assignment. Smith is without a definitive timeline for a return, but if he steers clear of any setbacks, he'll have a shot at rejoining the Detroit bullpen before the end of June.