MIAMI -- Losses have a tendency of weighing more heavily this time of year, especially on a team with playoff aspirations but facing an uphill climb like the Marlins.

So Friday's game against the Nationals will sting a little.

With the score tied in the sixth, an overworked Marlins bullpen gave up three runs in the next two frames and the offense couldn't battle back despite getting its chances, as Florida suffered a 5-3 loss in front of 15,247 at Land Shark Stadium.

The Marlins have still won seven of their past nine, but with the Phillies' 4-2 win over the Mets, Florida sits six games back in the National League East with just 21 contests left.

"I'd be lying if I sit here and say we don't watch the scoreboard and see what's going on," said reliever Brian Sanches, who gave up two runs in the sixth to give the Nationals a 4-2 lead. "Obviously, we have to take care of winning on our side, but yeah, it does hurt. You never want it to come down to one game that cost you [the playoffs], and there's a couple of games where hopefully we don't look back and say that."

Looking back on Friday, the Marlins can simply say this: Two inning-ending double plays cost them a chance at coming back.

Down, 5-2, in the eighth, Florida had runners on first and second with nobody out, but Jorge Cantu popped out, and John Baker bounced into a 4-6-3 double play off Mike MacDougal.

The ninth began with Dan Uggla making it a two-run game with a solo homer, his 28th on the year and third in his past three games. But with runners on first and second and no outs once again, Emilio Bonifacio struck out, and MacDougal got Chris Coghlan to ground into a 6-3 double play to end it.

"We had some people on base with the right guys at the plate, and they made some pitches, and they turned some double plays," said Marlins manager Fredi Gonzalez, whose team moved to 11-5 against the Nats this year.

"[MacDougal] needed to get a ground ball [in the eighth], and he got it," interim Nationals manager Jim Riggleman added. "The next inning was not as crisp, but ultimately he needed to get a ground ball, and he got it again."

With starter Josh Johnson out of the game after five innings, the Nationals took a two-run lead off Sanches in the sixth thanks to a two-run double by pinch-hitter Mike Morse. In the seventh, Ryan Zimmerman hit a solo home run off Andrew Miller, who was making his first big league appearance since July 19.

With rosters expanded this month, the Marlins have 11 relievers in the bullpen. But despite the extra arms, the relief corps has averaged more than four innings a night in its past four games.

"We've got the arms down there, and we're just going to continue to get the ball and go out there and try to put up zeros so we can get into the ninth inning for [Leo Nunez] to shut it down," Sanches said.

Going into his 29th start of the season, Johnson had already notched career highs in starts, wins, strikeouts and innings pitched. In his 12th career game against the Nationals, the 25-year-old right-hander was barely hit hard -- even Adam Dunn's two-run homer in the first inning looked like a fly ball off the bat -- but he battled a high pitch count and was unable to get into the sixth inning for his second consecutive start, with both coming against Washington.

"[Eighty nine] pitches in five innings, at this stage in the season, you have to keep an eye on him," Gonzalez said. "It's a concern, and the guy has over 188 innings and has never done it coming off surgery. You have to be aware of those situations."

Johnson finished giving up two runs on two hits while walking four and striking out eight, but he got his pitch count to 89 after five innings -- mainly because only 51 of those were strikes -- and couldn't put himself in line for his 23rd quality start of the year.

The Marlins' ace was consistently between 95-97 mph on his fastball throughout his entire outing. And even though he's already surpassed his previous career-high of 157 innings in 2006 by 31 1/3 frames, Johnson said his arm "feels great."

And he wanted to be out there.

"Absolutely I want to be out there," said Johnson, who pitched 87 1/3 Major League innings coming off Tommy John elbow ligament replacement surgery last year. "That's just the competitor I am, but there's nothing I can do about it. There's nothing I'm going to say that's going to change their mind.

"I understand where they're coming from, but at the same time, I want to be out there. If we lose the game, I want it to be on me. Not to go to the bullpen that early. But there's just nothing I can do about it."

After the Nats took a 2-0 lead, the Marlins came right back in the bottom half, when Hanley Ramirez took a first-pitch changeup from Washington starter J.D. Martin and sent it out to left-center field for a two-run homer, his 23rd of the year and fourth in his past six games.

But it wasn't enough.