Dan Haren took the mound on a warm and overcast Wednesday afternoon at Space Coast Stadium for the first time with new teammates behind him and a new jersey on his back, but with a familiar feeling in his gut: nerves.

One of the past decade’s most accomplished right-handed starters, a pitcher with three all-star appearances, the $13 million hired gun the Nationals hope will help put them over the top, was anxious for a late-February start. “If you’re not nervous, you shouldn’t even do this any more,” Haren said.

By the second inning of Wednesday’s 5-1 loss to the Miami Marlins, the jitters were gone . Haren, 32, who landed on the disabled list last season for the first time in his career with hip and back issues, showed his new teammates what made him such a durable and effective starter. The 11-year veteran allowed one run on two hits over two innings, displaying his array of cutting and biting pitches.

“I felt good,” he said later. “It was kind of a circus to start.”

Haren, in unlikely fashion, fell behind batters early. The second pitch of the game was drilled by a top Marlins prospect, Christian Yelich, deep to center field for a triple. (Yelich then scored on a sacrifice fly a batter later.) Haren, a good fielder, was charged with an error for misplaying a grounder hit back to him by Joe Mahoney, the game’s fourth batter, and making a late throw to first.

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“It’s not my game to be 1-0 or 3-0,” Haren said. “As the game started going, more first-pitch strikes and getting better looks.”

By the second inning, Haren grew more comfortable. Typical to his style, he kept the hitters off balance by changing locations and speeds. Batters reacted with check swings, fouls and awkward reactions. Haren said facing hitters is “a cat and mouse game more for me, rather than an overpowering game.”

Haren’s velocity stayed between 89 and 91 mph, touching 93 — slightly higher than the range he pitched at last season and a sign that he is healthy following his injury struggles with the Angels last season.

“As the spring goes along, it’ll get more crisp,” Haren said. “I’m not a guy when you’re going to watch me you’re going to go, ‘Wow. His stuff was just amazing today.’ It’s more of a thing where I just work to get people out. It doesn’t have to look good. I just want to get him out.”

In a rotation of hard throwers, Haren admits he will stand out, and provide a challenge to opposing hitters. “My fastball hovers around where Stasburg’s change-up is,” he said.

Haren came to spring training with a plan: to build arm strength, which is expected, and attack the right side of the plate, a particular weakness. He has traditionally hurt hitters with his arsenal of cutters and fastballs on the left side of strike zone. But late last season, when he was learning how to adjust to injuries and altered mechanics, he discovered success when pounding inside on right-handers and away against left-handers. And the victims Wednesday were Kyle Skipworth and Gorkys Hernandez, both strikeouts.

“It’s a different feel to go into a righty, where to start the pitch,” Haren said. “My game is all command, control, keeping guys off balance, in and out. That’s got to be a part of my game this year.”

Haren, a Southern California native, carries himself with a reserve. He is manwho believes in performance. He’s the “not that old” veteran, as he once referred to himself, of the Nationals’ relatively young starting rotation. He arrived in the clubhouse for Wednesday’s start around 9:30 a.m. and quietly got ready for his start.

By sheer coincidence, Haren’s locker sits to the right of Strasburg’s. The one pitcher Strasburg has repeatedly mentioned he wants to learn from this season is Haren. Growing up in San Diego, Strasburg caught highlights of Haren’s starts when he was with the Oakland Athletics and Arizona Diamondbacks and was always amazed at how much Haren’s pitches would move and the balance of his body during his delivery. Strasburg, more than anything, wants to emulate Haren’s durability. Haren has thrown at least 200 innings eight times since coming up in 2003.

“I want to be that type of guy, too,” Strasburg said. “A workhorse. You’re not always going to feel great. He said he takes pride in making his starts and that’s something I want to do.”

Slowly, Haren is adjusting to his new surroundings. Based on reports from his former teammates Chad Tracy and Adam LaRoche, Haren heard nothing but good things about his future teammates and the looseness of the clubhouse. Soon, the nerves will mostly be gone.

“You gain respect from your peers by going out there and performing and winning and doing well,” Haren said. “That’s how you get respect from people. My track record is good, but of course I want to go out there and compete and show the guys that I’m going to be good. I feel good with the way it went today, and there’s a long way to go.”