"We just couldn't put a zero on the board there. That was an important inning." manager Jim Riggleman, on the two-run sixth for the Mets.

Washington, D.C. -- As has been the case all season long, the Washington Nationals got an effort from their starting pitcher that "kept them in the game."  But not enough hits and the failure of two left-handed pitchers to do their jobs resulted in another close loss, this time 6-4 to the now-streaking New York Mets.

It's the fifth loss in six games for the Nats, lowering their record to 10-12, and the Mets fifth straight victory, upping theirs to 10-13.

The Nationals are now 1-11 when scoring fewer than five runs.

The Nats hit three solo home runs, two by Wilson Ramos and one by Jayson Werth, but stranded a leadoff base runner in three separate innings and went 1-for-9 with runners in scoring position.

Last night's key inning was the top of the sixth.  Jordan Zimmermann, who had given up three runs to that point on seven hits, got leadoff hitter Carlos Beltran to line out to Werth in right, but gave up a soft line drive to Jason Bay and a single to 1B Ike Davis.  It was at that point, after just 73 pitches, manager Jim Riggleman decided to lift his starter in favor of left-handed reliever Doug Slaten.

Slaten could not do his job, giving up a two-run double to left-handed batter Josh Thole, a line drive to left field that tailed away from Michael Morse into the corner.  Slaten has now allowed 8-of-18 inherited runners to score this season, though his personal ERA remains 0.00.

Did Riggleman consider allowing Zimmermann (1-4, 4.55) to pitch out of his own mess?  No, he did not.

"At that point, if anything, I maybe could have brought a left-hander in to face Davis, and I gave [Zimmermann] Davis," Riggleman said.  "Once Davis got the hit I felt like, you know, if we're gonna get beat here at that part of the order its going to have to be with a left-handed pitcher and unfortunately the ball was just out of reach in left field."

Zimmermann's line ended up kind of ugly: five earned runs on nine hits in 5 1/3 innings.  He only struck out one, but did not walk a batter.

"I thought [Zimmermann] threw the ball good," Riggleman explained. "Jordan's a great competitor and he was just leaving it all out there for us. I don't think he was quite at the top of his game as maybe he has been a couple of times previous, but he threw the ball good."

Considering that two of the runs charged to Zimmermann scored after he left the game, and two more scored as the result of an error in right field by Werth and a safety squeeze by pitcher Chris Young, Zimmermann's performance wasn't nearly as bad as the numbers look.

The Nats got back to within one run on Ramos' single to left in the eighth that plated Rick Ankiel, but Sean Burnett gave it right back in the top of the ninth.  After a leadoff bunt single by OF Jason Pridie against Brian Broderick (1.0 IP, 2 H, 1 ER), Burnett was called upon, as left-handed pinch-hitter Willie Harris had already been announced into the game, and the Mets had lefty Daniel Murphy in the hole.

Burnett hit both left-handed batters to load the bases, and David Wright's 1-4-3 ground out scored the insurance run right back.

When a team has as much trouble scoring runs as the Nationals do right now, every man has to do his job when called upon.  Last night, that just didn't happen.  It's a very thin line between victory and defeat for the Nationals right now.

They've got two more with the Mets then welcome the defending World Series champs, the San Francisco Giants for four games, before hitting the road against Philadelphia, Florida and Atlanta for nine games.  The next two weeks are going to tell us a lot about who the 2011 Washington Nationals really are.

THE GOOD: Wilson Ramos.  3-for-4, two home runs, RBI single. Hitting .378 this season.

THE BAD: Slaten and Burnett.  Both lefties allowed inherited runners to score, which ended up being the difference in the game.

THE UGLY: Matt Stairs flew out to left in his pinch-hitting appearance.  He's now 0-for-12 to start the season, and Nats pinch-hitters are 1-for-24 in 2011.

THE STATS: 1-for-9 with RISP, 6 LOB.  Eight hits, two walks, six Ks.  E: Werth (3)

NEXT GAME: Wednesday at 7:05 vs. New York Mets.  Tom Gorzelanny (0-2, 4.96) faces R.A. Dickey (1-3, 4.10).

NATS NOTES:  SS Ian Desmond was placed on the 3-day Paternity List to be with his wife Chelsey for the birth of their first child.  OF Roger Bernadina was recalled from AAA Syracuse to take his spot on the roster.  Bernadina entered the game in a double-switch and lined out to David Wright with two outs in the ninth inning.

Ryan Zimmerman resumed some light activity at the park today, but there is still no timetable for his return to the lineup.  He will probably need a rehabilitation stint in the minors once he's ready to fully participate.  It's highly unlikely he'll make an appearance in a game at Nats Park in this homestand, which ends Sunday against San Francisco.