DJ Herz throws first game innings in nearly two years after Tommy John surgery

What happened

Washington Nationals left-hander DJ Herz returned to game action Friday for the first time in nearly two years, throwing two scoreless innings in the Florida Complex League. Per MLB Trade Rumors, it marks Herz's first competitive appearance since he underwent Tommy John surgery at the beginning of the 2025 season. The outing is described as the start of a buildup expected to last more than a month.

Two scoreless innings in the FCL is, by design, the quietest possible re-entry into professional baseball. The FCL exists precisely for this kind of careful reintroduction — low stakes, controlled environment, the organizational equivalent of easing back into a cold pool one toe at a time. The fact that Herz got through it without incident is the entire point.

Why it matters

Herz is not a depth afterthought. He came to Washington from the Cubs as part of the 2023 Jeimer Candelario deadline trade, and he made good on that pedigree in his rookie season, starting 19 games for the Nationals. Per MLB Trade Rumors, he posted a 4.16 ERA that year while striking out nearly 28% of batters faced — and was identified as the top swing-and-miss arm in the Washington rotation.

That last detail is the operational crux. The current Nationals starters are described by MLB Trade Rumors as middle of the pack in strikeout rate this season, and the rotation sits in the bottom third of MLB with a 4.59 ERA, a figure the report attributes largely to one of the sport's highest home run rates. The rotation has shown improvement of late, though MLB Trade Rumors notes that improvement has come with heavy usage of openers. The underlying settled rotation — the arms actually being handed the ball as starters — has remained fairly consistent across the season.

A pitcher who generated whiffs at a nearly 28% clip as a rookie, and who was the best swing-and-miss option in the building before his injury, is exactly the profile a rotation like this one is missing. Whether Herz can recapture that after Tommy John surgery and nearly two years away from game action is the question that will take considerably longer than a month-plus buildup to answer — but Friday was the first data point.

The numbers

The Nationals' rotation ERA of 4.59 and the home run rate context come from MLB Trade Rumors' framing of the current staff. Herz's own line from his rookie year — 19 starts, 4.16 ERA, strikeout rate approaching 28% — is the baseline against which his eventual return will be measured. He was, per the report, the rotation's leading swing-and-miss arm that season, which gives those numbers a bit more texture than a raw ERA line usually provides.

The Nationals' current record sits at 77-85 (.475), placing them 4th in the NL East, 17 games back in the division. They are eliminated from both the division race and the Wild Card race, with a Wild Card rank of 8 and 11.0 games relative to the cut line. Washington enters this week on a one-game winning streak.

Where the club stands

The Nationals are 77-85 (.475), fourth in the NL East and 17 games back of the division lead. They are eliminated from the division race and from Wild Card contention, sitting 11.0 games outside the cut line at rank 8 in the Wild Card standings. They carry a one-game winning streak into the week.

The schedule ahead takes Washington to Oracle Park on Tuesday, where Andrew Alvarez is the probable starter against Adrian Houser for San Francisco. Foster Griffin follows on Wednesday against Robbie Ray. The club returns home Friday to host the Seattle Mariners at Nationals Park, with Zack Littell projected to start opposite Bryce Miller.

None of those names is DJ Herz, which is the point. The month-plus buildup described by MLB Trade Rumors means the rotation questions for this particular road trip and homestand will be answered by the arms already in the mix. Herz is a longer-horizon story.

What we don't know yet

The report describes the buildup as "likely" to last more than a month, which is a projection, not a timetable. No specific return date or target has been reported. It is also not yet known what the next step in Herz's progression looks like — whether that means additional FCL outings, a move up to a higher affiliate, or an increase in pitch count and inning load. Two innings is a starting point, not a blueprint.

Under general league mechanics, a pitcher on a rehab assignment has up to 30 days before a club must make a decision on activation or a roster move. Whether Herz is currently on a formal rehab assignment or simply rehabbing in the FCL outside that structure has not been reported.

What his stuff looks like — velocity, movement, command — after nearly two years away is entirely unaddressed by the available reporting. Friday's outing tells us he got through two innings without incident. It does not tell us whether the swing-and-miss profile that made him the rotation's best whiff generator in his rookie year has survived the surgery and the layoff. That will take more outings, more data, and more time.

What to watch

The obvious follow-up question is straightforward: when does Herz pitch next, and at what level? Each successive outing will carry more information than the last. A move from the FCL to a full-season affiliate would signal that the buildup is progressing on schedule. An increase in innings — from two toward something resembling a starter's workload — would be the more meaningful milestone.

For a Nationals rotation that MLB Trade Rumors describes as sitting in the bottom third of MLB in ERA and carrying one of the sport's highest home run rates, the eventual return of a left-hander with Herz's strikeout profile would represent a genuine addition. The rotation has been more settled than its results suggest, and the opener-heavy recent stretch has papered over some of the underlying ERA concerns without necessarily resolving them.

Herz is not a solution for June. He is, at best, a question worth revisiting in late summer — and only if the buildup proceeds without setback. For now, two scoreless FCL innings is the whole story, and it is a better story than the alternative would have been.