Only two full weeks into the season, there is still plenty of time for firsts for the Nationals. They’ve already had their first squeeze bunt (Rick Ankiel’s bunt in the second game of the season) and their first extra-inning win ( a 5-3 victory over the Florida Marlins on April 7 ). And after Saturday, they welcomed their first rainout thanks to an endless bout of stormy weather.

So with that, the Nationals adjusted and took advantage of an extra day off — especially projected first-game starter Jason Marquis — for a doubleheader on Sunday against the Brewers. Manager Jim Riggleman took the time to reflect briefly on some of the team’s early strengths.

After blowing a one-run lead with two outs and two strikes in the ninth inning to the Milwaukee Brewers on Friday night, Riggleman expressed confidence in late-inning reliever Sean Burnett. Carlos Gomez’s single plated Rickie Weeks to tie the score at 3 in the ninth — a game the Nationals later won, 4-3, in the 10th inning.

After converting the previous three saves, it was only Burnett’s first slip-up in his new role. The plan to use him in the ninth inning to finish out games won’t change, Riggleman said.

Burnett “made some really good pitches and then he made a pitch I’m sure he wishes he had back,” Riggleman said. “He didn’t get the ball down and in enough and kinda left it out there a little bit and Gomez got him. You know, that happens. But I thought [Burnett] was very effective. They put a couple hits together.”

The winning difference in Friday’s game — the aggressive late-inning baserunning of Jayson Werth, who scored on an infield bouncer by Adam LaRoche — is an example of the style of play the Nationals have been hoping would carry over from spring training to the season. The efforts of Werth, an experienced player and World Series champion with the Philadelphia Phillies last season, will hopefully rub off in the Nationals clubhouse.

“I think that really will sink in with a lot of players,” Riggleman said. “However, that’s been going on since the beginning of spring training. Really, from day one of spring training, as every club in baseball and as we have always done, really have preached that message: ‘Let’s be aggressive, lets go first to third, lets challenge infielders and all that stuff.’ However, it quite often doesn’t carry into the season. But again, I give [third base coach] Bo Porter a lot of credit. Bo has made sure that, with our baserunners, to maintain that aggressiveness. That’s not a spring training thing, that’s something we want to do throughout the season. And our players have really absorbed that message.”

Zimmerman update

A week into third baseman Ryan Zimmerman’s recent aggravation of a troublesome abdominal strain, the Nationals continue to approach the health of their best player and No. 3 hitter cautiously. Zimmerman, who has sat out since re-injuring the muscle, has been out since Sunday and was placed on the 15-day disabled list on Tuesday.

“I’m not even talking about it with [Zimmerman] because I don’t want any of us to keep asking and making him feel that we’re pushing him to get back,” Riggleman said. “I want him to come back on his timetable. I think in spring training we thought a week or whatever, ten days, was going to do it. But obviously it wasn’t enough. I think we have really gotta let him and Lee Kuntz, our trainer, tell us and let the doctor check him out again and they’ll tell us. For us to keep asking is really not getting anywhere.”

Sunday’s starters

With Marquis (0-0, 3.65 ERA) pitching the 1:35 p.m. game, Livan Hernandez (1-1, 3.50 ERA) will take the mound in the second matchup of Sunday’s doubleheader against the Brewers. Hernandez had been originally scheduled to pitch Sunday afternoon.