Nationals Pull DJ Herz From Rehab After Flexor Muscle Strain Setback

The Washington Nationals have shut down DJ Herz’s rehab effort after he suffered a flexor muscle strain, a development that complicates a return timetable for the left-hander coming back from Tommy John surgery last year. The setback is notable not only because of what it interrupts, but because the Nationals believe it is muscular rather than another ligament issue, which often carries different recovery timelines and risk profiles.

Nationals manager Blake Butera told reporters that Herz was taken off his rehab assignment following the flexor strain. The reporting was carried by ’s Byron Kerr as part of Butera’s remarks. MLB Trade Rumors described the injury as a flexor muscle strain that surfaced during recovery from the elbow procedure that sidelined Herz in 2025.

Herz’s situation highlights the thin margin teams try to manage when a pitcher works through the progression from post-surgical throwing to increased intensity. After Tommy John, organizations typically monitor not just the surgically repaired elbow, but also the surrounding forearm and flexor mass that can be stressed as mechanics change during the early phases of rebuilding. In that sense, a flexor strain can be both a consequence of ramp-up and a new limiter on innings, effort, and workload.

For Washington, this is a roster-building issue as much as a medical one. Herz’s progression mattered because left-handed starting depth is harder to replace internally once the season is underway, particularly when organizations are also planning for bullpen usage and long relief. A disruption to a starter’s rehab plan can force the club to re-evaluate who can give multi-inning work, who covers spot starts, and how the staff manages day-to-day workload during the stretch of the schedule where pitch counts and rest become harder to line up.

MLB Trade Rumors framed the bright spot of the update as the nature of the injury. If the problem is muscular, it can still be serious and time-consuming, but it is generally distinct from a repeat elbow ligament setback. That distinction matters because it affects how aggressively the team can progress Herz through throwing without re-triggering the underlying vulnerability that brought him to Tommy John in the first place.

At the same time, the Nationals’ next steps will likely be cautious. Even when a strain is not ligament-related, flexor injuries can flare when pitchers push beyond what the tissue can tolerate. The practical takeaway for Nationals fans is that Herz’s return is now subject to re-assessment after the team gives the forearm and flexor area time to settle, then rebuilds intensity in a controlled progression that may or may not mirror the original plan.

What to watch next is whether Washington provides any additional clarity on the rehabilitation window, including how soon Herz resumes throwing and what benchmarks the organization uses before he can rejoin a high-leverage role in games. Until then, the move indicates a pause in any near-term expectation for the left-hander to return from the injury reserve path that followed his Tommy John surgery.