Nats place Herz on 15-day IL with UCL sprain in elbow

The Nationals placed DJ Herz on the 15-day injured list this morning with a UCL sprain in his elbow, a potential season-ending ailment for the left-hander that would explain his spring training struggles.

Herz had been optioned to Triple-A Rochester on Friday, capping off a difficult spring that saw the 24-year-old deal with diminished velocity and poor results while ceding the No. 5 starter competition to fellow lefty Mitchell Parker.

At the time, club officials suggested Herz simply needed more time to get his arm in shape and that he would be in the running for a promotion back to the majors once he looked more like himself.

“We know his velo was a little bit down, but just go down there and start getting built up,” manager Davey Martinez said Friday after the demotion was announced. “And understand that last year, he only had (19) starts. He hasn’t pitched that much. So he’s going to go down there and get ready to help us.”

Herz was one of the brightest developments of the 2024 season for the Nationals, called up to make his major league debut in early June and then remaining in the rotation for most of the remainder of the year. He finished with a 4-9 record and 4.16 ERA, but he authored some of the team’s most dominant starts of the season, including six innings of one-hit ball with 13 strikeouts against the Marlins on June 15 and 10 strikeouts with one run allowed July 2 against the Mets.

Acquired from the Cubs in a 2023 trade deadline deal for third baseman Jeimer Candelario, Herz went to camp this spring in an open competition with Parker and Japanese free agent Shinnosuke Ogasawara for the final spot in the Nats rotation. He struggled in each of his four starts, though, finishing with a 6.52 ERA and 1.966 WHIP. He walked nine batters while striking out four in only 9 2/3 innings.

It all came to a head March 13 against the Rays in Port Charlotte, where Herz’s fastball topped out at 91 mph (he averaged 93.5 mph last season) and the Nationals held him to three innings when other starters were going five.

Herz attributed his struggles not to any kind of injury but a lack of adrenaline and issues he dealt with in prior springs.

“Look at last year, and then look at the years before: My velo’s always down in spring training, my command is all over the place,” he said that day. “Spring training hits me a lot harder than, I would say, most people. And I’m kind of going through that right now. I’m trying to grind through, get through these ones, until my arm is good.”

The Nationals opted not to use Herz in another Grapefruit League game after that. He instead threw 85 pitches over five innings in a simulated game five days later, one that appeared to show signs of progress.

“He threw the ball better,” Martinez said after that March 18 session. “The strikes were more competitive. The balls were even more competitive. His changeup had good shape. He was up at 92 with some pitches, which is better. So all in all, he was a lot better today.”

That was Herz’s final time throwing to live hitters in big league camp. He and Ogasawara were optioned to Triple-A three days later. Now, four days after that, he has been placed on the IL with an elbow sprain, the severity of which has not yet been disclosed.

If doctors determine surgery isn’t necessary, Herz theoretically could attempt to rehab and return sometime this season. If the sprain is more significant, he could be looking at Tommy John surgery and/or an internal brace procedure, which would sideline him until 2026.

Herz’s injury comes one season after Josiah Gray tore his UCL, requiring Tommy John and the internal brace. Cade Cavalli suffered the same injury in March 2023 and is still attempting to make it all the way back.