"It's a game of peaks and valleys, and we're definitely in a valley right now," Venable said.
Whether it's a downpour or a deep valley, San Diego (37-58) can't seem to get much right lately. It had just three hits Wednesday and finished a seven-game homestand at 1-6, having not won a series since the last weekend of June. The loss dropped the club to 3-16 in July.
"You're going to have some inconsistency with young guys," Headley said. "We understand that we are young and will take some lumps, but we can't accept it."
Marlins pitcher Ricky Nolasco limited the Padres to just two hits in 6 1/3 scoreless innings. He walked three and fanned 10.
Outfielder Kyle Blanks singled in the second, which was the Padres' only hit for the first six innings.
"We have a number of guys struggling at the same time," manager Bud Black said. "To do well, you need four, five or six guys swinging well. We don't have near that."
The Padres had their first legitimate chance to erase a 2-0 deficit when the offense showed signs of life in the seventh.
First baseman Adrian Gonzalez led off with a walk, but third baseman Kevin Kouzmanoff, who went 0-for-4 with four strikeouts, struck out for the first out. Outfielder Drew Macias singled to right field and Blanks walked to load the bases with one out.
"We had a couple of opportunities there to get the game back at even or maybe go ahead," Black said.
But the Padres didn't take advantage of the best situation they created. Reliever Brendan Donnelly replaced Nolasco and retired shortstop Luis Rodriguez and Headley, who struck out looking on 3-2 pitch and displayed visible frustration.
In retrospect, Headley thinks he should have attempted to foul off the "borderline" pitch, an 88-mph slider.
"I was about to start to first," he said. "[The frustration] was more in the fact that the call was late."
Donnelly said retiring two consecutive batters with the bases loaded was a "big moment," essentially knocking the wind out of the Padres' comeback chances.
"I was fortunate to get the [Rodriguez] popup in the infield that wasn't deep enough to be a sac fly. I was fortunate with that," Donnelly said. "Headley came up. He was putting up a pretty good at-bat, and the call was the call."
Padres starter Josh Geer (1-6) said he gave his team a chance to win, which is all that he could strive to do.
"I felt really good today," he said. "I was keeping it down in the zone."
Geer tossed six innings, allowing two runs on six hits. He struck out four and walked one in his eighth quality start this season, a start with three or fewer earned runs in at least six innings.
"We'll take that anytime," Black said.
Florida right fielder Jeremy Hermida homered off Geer to put the Marlins on the board in the second inning.
"I hung the slider a bit," Geer said.
Second baseman Dan Uggla produced the Marlins' second run on a line-drive single in the sixth, scoring shortstop Hanley Ramirez.
Padres reliever Mike Adams allowed one unearned run in the eighth. Left fielder Chris Coghlan scored after Hermida reached second on Padres shortstop Everth Cabrera's throwing error.
Coghlan hit a two-run homer to right-center field off closer Heath Bell in the ninth, extending Florida's lead to 5-0.