Kelvin Herrera has allowed more runs in 9 2/3 innings since being traded from the Royals than in the previous 25 2/3 before the deal. (Carolyn Kaster/AP)

NEW YORK — Kelvin Herrera doesn’t say much in the clubhouse. He would never be the most talkative man in this group of Nationals relievers, a title more hotly contested than most division races these days. Herrera wouldn’t even be in the running. He mostly keeps to himself.

Herrera knew everyone in Kansas City. He cried when he left. He jokes around when joked around with, smiles when smiled at, and shows no signs of surliness. But he does seem like the new kid at school sometimes, still finding his way — particularly on the field.

After an adventuresome eighth inning in Thursday night’s win, Herrera is pitching to a 4.66 ERA in 10 outings as a National. He has allowed more runs (five) in 9 2/3 innings since the trade than he did (three) in 25 2/3 innings before it. His strikeout-to-walk ratio with the Royals was 11.00. It dropped to 1.67 with the Nationals.

Herrera downplayed the impact of all the adjustments the trade required.

“It’s the same baseball,” Herrera said through team interpreter Octavio Martinez. “It’s a different role, but it’s the same baseball. You just have to maintain yourself and stay positive.”

Herrera doesn’t need an interpreter for most conversations. His English is excellent. But part of adjusting to a new organization is wanting to make sure every word is perfect. He doesn’t want any misunderstandings.

So when asked about how he is handling his increased workload with the Nationals — he has appeared in 10 of 23 games since the deal — Herrera used the interpreter to send the message. He doesn’t mind. He just has to be careful, particularly as he continues to switch between roles. He is the closer in Sean Doolittle’s absence, though he pitched the eighth because of matchups Thursday night. Some of those roles require more back-to-back days than others.

“I think all I really have to do at this point is find better exercise to keep my arm healthy,” Herrera said. “Creating a good rhythm so I can keep helping the team win games.”

That Herrera brought up the health of his arm could be cause for concern. He often shakes and tests his forearm between pitches, something some Nationals pitchers do more than others — something that is cause for alarm for some of them, and a nonissue for others. As he talked about his outing Thursday night, in which he struggled to spot his fastball and walked two, Herrera mentioned something else that raises concern: extension.

“I was having a little trouble getting extension on the ball,” Herrera said through Martinez. “I was able to increase it as it went along.”

Brandon Kintzler landed on the disabled list when he started struggling to get extension. In his case, a lack of extension came from increased tightness. Then again, perhaps conjecture like this is why Herrera wants to be so careful with his words in the first place. Perhaps the problem was just mechanical. He did not say anything about pain.

Still, the Nationals’ newest reliever is important to their plans both because of his abilities and what he presence means for the workloads of his colleagues. The Nationals need Herrera, who is available to close Friday night despite a high pitch count Thursday. The biggest adjustment he might face will be to his workload.

In other relief news, Koda Glover will begin a rehab assignment with Class A Potomac this week. The reliever has not pitched since last June due to rotator cuff inflammation.

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