The Washington Nationals have not yet exhausted one full week of their spring training schedule, but Ross Detwiler, relegated to the bullpen by a crowded rotation, can already envision the kind of season he may have ahead. “Being a long reliever on this team,” Detwiler said with a laugh, “is not going to be very fun.”

It is still early, far too early to shape any firm conclusions or for the line scores to matter. But after one cycle through their rotation, the Nationals’ reshaped starting five has pitched as well as the team could have hoped, like a staff that will not need much bailing out from a long man looking for work.

Thursday afternoon, Edwin Jackson threw four scoreless, two-hit innings against the Houston Astros in his second start this spring. After his breezy outing, Nationals starters have produced 12 consecutive scoreless innings, and with John Lannan as the fifth starter, they have a combined 1.62 ERA over 162 / 3 innings.

When the Nationals signed Jackson, traded for Gio Gonzalez and welcomed back Stephen Strasburg, they formed a rotation they believed would allow them to contend in the National League East. Their first glimpse at it, even if it came during meaningless games, gave them a hopeful preview.

“It’s no secret that Philly has some of the best pitchers in the game, and we’ve got to compete with that in the NL East,” Detwiler said. “So I think going out and getting the starters we did, getting the bullpen we did, I think we’re in a very good spot.”

The quality of the Nationals’ rotation can be gleaned not just by who is in it, but by who will not be in it. Lannan, their opening day starter in 2009 and 2010, is competing with Chien-Ming Wang for the fifth spot. On Saturday, Lannan will pitch against the Detroit Tigers while Wang faces the New York Mets here.

Detwiler, the sixth overall pick in the 2007 draft, posted a 3.20 ERA in nine starts at the end of last season. Thursday, he retired all nine hitters he faced, striking out three, while his late-moving fastball zipped between 91 and 93 mph. His output in past springs would have likely ensured him a spot near the top of the Nationals’ rotation. This year, he’s slated for the bullpen.

“Any other circumstances but for where this staff is, I probably would’ve let him go another inning,” Manager Davey Johnson said. “But we have other guys that need work.”

The Nationals gave themselves their pitching depth when they signed Jackson in February. In his first start, Jackson walked two batters and, while he didn’t yield any runs, never found comfort on the mound. He pitched with a modified wind-up, standing cocked to the side with one foot on the rubber. He worked on new mechanics, trying to hide the ball from hitters and not tip his pitches.

Thursday, Jackson found comfort with his new mechanics by forgetting about them. He pitched from his old wind-up, two feet on the rubber, standing tall on the mound. And he dominated. Only two Astros reached, both on singles, and he struck out three using a vicious slider and a deceptive change-up.

Between starts, pitching coach Steve McCatty had told Jackson to “be an athlete,” and not worry about his form. Jackson found a rhythm early Thursday, and he stayed in it.

“When it’s going good, you really don’t know what you’re doing,” Jackson said. “You’re just doing it. See the pitch and throw the ball to the glove. That’s pretty much the approach you have to take sometimes. Free-minded, not thinking about anything, just throw it to the glove.”

From the time Jackson signed, the Nationals have discussed tweaking his wind-up to make it more difficult for batters to pick up the ball. But while Jackson prepares for his season, they don’t want the new adjustments clogging his head.

“You can quit writing about his mechanics and all that B.S.,” Johnson told a group of reporters. “He was as good as it gets right there. Everything about him. He looked completely relaxed and normal. His stuff is outstanding, but everything about him was outstanding — his delivery, everything.”