WASHINGTON — When Hunter Harvey took the mound for the top of the fifth inning Tuesday night against the Orioles, he felt a type of adrenaline that hadn’t coursed through his veins in a long time.

It wasn’t because he was trying to help the Nationals protect a 3-2 lead. Nor was it because he was coming back out for a second frame after pulling an escape artist act in the fourth. No, this inning was one he had been thinking about for a long time.

Harvey, 27, was a 2013 first-round pick of the Orioles. This Baltimore team chasing a playoff spot stocked with budding, young stars was supposed to include him at the center of it. Instead, injuries and a lack of consistency led the Orioles to subject him to waivers, which allowed the Nationals to scoop him up earlier this season.

“That was like debut adrenaline,” Harvey said after the game. “It don’t come around very often. So it’s hard to say this how you handle that. I tried to get out of the middle as much as I could but of course the one guy I couldn’t is the worst guy possible.”

When he faced the top of the Orioles’ lineup in the fifth, it included several players he spent years playing with in the minor leagues. The “worst guy possible” was Ryan Mountcastle, one of his closest friends. Harvey and Mountcastle talk every day. The slugging first baseman was in his wedding and they lived together during spring training in 2018.

So when Mountcastle crushed an 0-1 pitch to the opposite field for a home run, Harvey couldn’t help but start laughing.

“Yeah, I started laughing,” Harvey said. “That’s the first time I ever laughed giving up a home run. I just couldn’t -- it was hard to kind of hide that emotion just because we’re so close. We’ve talked so much trash, when that happened he looked at me and was laughing. I knew my phone was gonna get blown up. I knew he was gonna wear me out. I was like, this is the worst-case scenario. I was also telling him I was gonna hit him so probably should’ve just done that.”

The at-bat lasted only two pitches. Harvey blew the first one 98 mph past a swinging Mountcastle, but he left it over the plate more than he would’ve liked. He tried to get off to the side with his second offering -- this one at 99 -- but it stayed over the dish enough for Mountcastle to get ahold if it.

Mountcastle’s blast proved to be critical, tying the game at 3-3 before Austin Hays put Baltimore in front for good with an RBI double four batters later. But for Harvey, this was about more than a Tuesday night game in September.

“We’ve been back and forth since we met,” Harvey said. “I think I got him out in minor-league camp one time. He got a single that went through the legs of the outfielders and he got a triple. He’s been talking crap about that since, that was 2015. And we’ve been together on the same team the last four or five years. We’ve always talked about, ‘What if we got to face off?’ And we did. He might have won tonight but that’ll be the last time.”

Harvey wrapped up his postgame scrum with the media and pulled out his phone as he walked toward the tunnel. His phone was ringing. It was Mountcastle.