WASHINGTON, D.C. -- Just wait until the big guns get back. Or so the thinking went in D.C. as the offensively challenged Nationals struggled to score runs in recent weeks.

Since July 10, when leadoff hitter Denard Span joined blue-chip bats Anthony Rendon, Jayson Werth and Ryan Zimmerman on the disabled list, the Washington lineup has been on life support. Over the past three-and-a-half weeks, the Nats rank 26th in baseball in runs per game (3.37), 27th in batting average (.224), 28th in OPS (.637) and 29th in on-base percentage (29th). Prior to that, Washington ranked 10th, 13th, 11th and 11th in those categories respectively.

Rendon came off the DL on July 25, and three days later, Werth and Zimmerman followed. But in the six games since, the Nats are still having trouble scoring, averaging just 2.3 runs per game (29th in MLB over that stretch). So what gives?

The Nationals are just 28-40 over the last three seasons with Denard Span out of the lineup. Patrick Smith/Getty Images

For starters, it appears that, WAR be damned, the one player the Nationals can least afford to do without is still missing. That would be Span. Since coming to Washington in 2013, the speedy center fielder hasn’t ranked among the team’s top three in WAR (wins above replacement) for an entire season. Two years ago, his 2.3 WAR was sixth on the team and well behind Werth, whose 4.7 led the club. Last season, Span’s 3.7 ranked fourth on the Nats, whose WAR leader was Rendon (6.6).

However, over the last two-plus seasons, Washington’s win-loss record suggests that Span has been their linchpin. During that time, Werth, Zimmerman and Rendon each have missed at least 118 games. Without Werth, the Nats have posted a .508 winning percentage (60-58). Without Rendon, they’re playing at a .527 clip (79-71). Without Zimmerman, they’ve played .535 ball (84-73). But in the 68 games that Span has missed since the beginning of 2013 (including 44 this year), the Nationals have posted a sickly .411 winning percentage (28-40).

“Getting him back is going to be really important,” first baseman Clint Robinson said. “He’s a game changer for us.”

Earlier Monday, Nationals manager Matt Williams said that Span, who has been doing light work in the outfield and hitting in the cage as he recovers from back spasms, is getting closer to returning. That said, Williams stopped short of giving a timetable.

In the meantime, one thing that should help Williams’ offense wake up is facing mere mortal pitchers. Over the past 15 games, the Nats’ list of opposing pitchers practically reads like a Cy Young ballot: Clayton Kershaw, Zack Greinke, Matt Harvey (twice), Jacob deGrom (twice), Noah Syndergaard (twice), Francisco Liriano, A.J. Burnett, Gerrit Cole, Jose Fernandez and Dan Haren. After being swept by the Mets over the weekend to fall back into a tie for the National League East lead with New York, the Nats return home on Monday to face the Arizona Diamondbacks and rookie hurler Zack Godley.

When asked how facing Godley -- a former 10th-round pick who posted a 5.14 ERA at Double-A Mobile this year, but who has won his first two big league starts -- compares to the gauntlet his team endured the last two weeks, Williams denied any sense of relief.

“Doesn’t matter,” the Nats’ bench boss said. “Every time he’s gone to the mound, he’s won. We still have to do things at the plate that will allow us to win the game.”

Scoring runs would be a good start.