President of Baseball Operations Larry Beinfest on Friday said among the challenges of adding more pieces to the Marlins before the July 31 trade deadline is identifying the biggest need.

"On a daily basis it seems to change," Beinfest said.

After Friday's 5-1 second-half opening loss to the Nationals, the Marlins could use more starting pitching, more hitting, more alert defenders and better baserunners. That about covers it.

Hosting the first-place Nationals in the first of four, the Marlins failed to even modestly distance themselves from a disappointing first half. Starter Jordan Zimmermann and a slew of relievers combined to hold the Marlins to seven singles. Two of those belonged to Carlos Lee, who made his Marlins Park debut as a member of the home team.

"Overall, the biggest thing we saw was the offense just wasn't clicking and it was the No. 1 thing that I think we felt most confident in coming into the season," Beinfest said. "We had to make the move with Carlos and sure enough we lose Giancarlo almost right on cue when we make the trade. That's the way it goes. If you want to be a good team, you have to overcome things."

Friday, the Marlins couldn't overcome a five-run deficit. Starter Josh Johnson didn't set the tone. The Nationals tagged him for five runs on 11 hits through 5 1/3 innings. It was the fifth time in 131 career starts he allowed a double-digit hit total. Four of those outings have come this year, including a career-high 11 hits twice. He also gave up that many over 3 2/3 innings in an April 11 loss to the Phillies.

Johnson also allowed five runs in his first-half finale, a July 4 no-decision at Milwaukee. Before that, he was 5-2 with a 2.46 ERA during a 10-game stretch (65 2/3 innings) that saw his season ERA dip from 6.61 to 3.80. It's back up to 4.28.