(Photo by Rob Foldy/Getty Images)

Tanner Roark wants badly to make the Nationals’ pitching staff, either as the No. 5 starter or in the bullpen. Taylor Jordan, another rookie vying for the fifth spot, admitted after his last start that the uncertainty made him nervous. Not Roark. He insists his place in the competition does not cross his mind when he takes the mound.

But parts of Roark’s 3 1/3-inning performance will stay with him. He could not abide the two walks he allowed in the first inning. Roark makes his living with command – in his breakout 2013 season, he walked only 1.7 batters per nine innings in the majors and minors combined.

“I’m my biggest critic,” Roark said.

Wednesday afternoon in the Nationals’ 10-9 loss to the Astros, he walked two hitters in the first inning. He got ahead of leadoff hitter Dexter Fowler, 0-2, and then walked him. He also walked cleanup hitter Marc Krauss with two outs. He threw 37 of 62 pitches for strikes, a small ratio for him.

In between the walks, Roark allowed a double to Jason Castro on a fastball he left high in the zone. After the first, Roark consulted with pitching coach Steve McCatty. He realized he was moving too quickly through his delivery. He stayed back for the remainder of the game. Even though he yielded a wind-aided homer to Castro – which came after right fielder Eury Perez botched a wind-blow pop-up – he was happy with the rest of his outing.

“I felt I had more command of my offspeed,” Roark said. “Got a feel for it finally. That has a lot to do with staying back, so you can stay on top of the ball and get through it better.”

In regard to the competition, Roark and Jordan are probably both behind incumbent Ross Detwiler. Between Jordan and Roark, Jordan won this round – he struck out six of the 12 batters he faced in his last start and had Nationals officials raving about his offspeed pitches.

>>> Craig Stammen had lobbied McCatty to throw more during games, and today he got his wish. Stammen recorded seven outs over three innings, entering with one out in the fourth and leaving with two outs in the sixth. He feels like his sinker and his slider click once he builds his arm strength, and today he could feel both pitches improving.

Stammen allowed four singles, all either bloops or grounders, but struck out four out of five batters in one span.

“Today was a big step forward for me,” Stammen said. “I felt pretty good out there, especially the second inning that I threw. I felt like my stuff was moving. My slider was a little bit better, even though I threw some pretty bad ones today, too. They had two bloop hits and three ground ball hits. I can’t really complain about that. When I faced their top five hitters, in between the first, second and third inning, I struck four out of the five out. It’s a positive I can take away.”

When Stammen left, he passed the baton to lefty Jerry Blevins, his former college teammate and the only other Dayton Flyer in the major leagues.

“In Dayton, it was always the opposite,” Stammen said. “He would start, and I would come in and be the closer. It was a little backwards today, but he did a good job coming in after me.”

>>> Jamey Carroll had a good day for his chance to make the roster. Taking the place of Ian Desmond, who was  a late scratch with a cut on his right pinky, Carroll smoked a triple to the left-center gap and ripped a line-drive single to left. With his two hits, Carroll matched his prior total for all of spring. He also handled several plays at shortstop, his good footwork making up for average arm strength.

>>> Left-hander Xavier Cedeno experienced his first hiccup of the spring. He allowed a hail of hard-hit balls and three runs as the Astros erased a two-run deficit in the ninth. The inning unhinged when right-fielder Steven Souza Jr. lost a fly ball in the sun, and so Matt Williams gave him a pass. “He threw good,” Williams said.

>>> Reliever Aaron Barrett retired all four hitters he faced, striking out two. He has yet to allow an earned run this spring in seven innings over six appearances. He has a good chance to start the year as Class AAA Syracuse’s closer, and he could help the Nationals sometime this summer.

>>> Outfielder Nate McLouth socked his first homer of the spring off left-handed reliever Darin Downs. Last year, four of McLouth’s 12 homers came against left-handed pitching.