Alzolay (forearm) threw a 30-pitch bullpen session Tuesday, Taylor McGregor of Marquee Sports Network reports.
Alzolay appears to have responded well to what was his first time throwing off a mound since he was shelved with a flexor strain in mid-May. Before coming off the 60-day injured list, Alzolay will need to make multiple rehab appearances in the minors, and it's unclear when he might be ready to begin an assignment.