What D-backs' Ugly Series Loss to Nationals Told Us — And What It Didn't

A rough series for Arizona.

Jun 5, 2026; Phoenix, Arizona, USA; Arizona Diamondbacks pitcher Merrill Kelly (29) throws against against the Washington Nationals during the first inning at Chase Field. Mandatory Credit: Arianna Grainey-Imagn Images | Arianna Grainey-Imagn Images

The Arizona Diamondbacks, needing to continue their momentum after a series split with the Los Angeles Dodgers, could not come away with a series victory in their three-game set with the Washington Nationals at Chase Field.

Here's what a somewhat-ugly series against Washington told us, and what question remains as a result.

What Diamondbacks' series loss to Nationals told us

Concerning situational offense

Arizona Diamondbacks batter Ketel Marte (4) high-fives teammate Tommy Troy (9) after his 2-run home run against the Los Angeles Dodgers at Chase Field in Phoenix on June 1, 2026. | Joe Rondone/The Republic / USA TODAY NETWORK via Imagn Images

The Diamondbacks' offense, despite bursts of excellence from Ketel Marte and Corbin Carroll, has simply struggled to build innings — and, more importantly, cash in on the opportunities to score they do manage to afford themselves.

That was a glaring weakness of Arizona's lineup in this three-game series. The Diamondbacks plated only two runs between games one and two, against a pitching staff that ranks sixth-worst in the majors in ERA (4.61).

After being blown out 14-1 in game one, the D-backs picked up just two hits against Zack Littell in game two. Littell had an ERA north of 5.00 coming in to Saturday's game.

But more critically, Arizona could not find a way to bring runners home once on base. They turned in a dismal 1-for-12 performance with runners in scoring position in this series, including an 0-for-7 day in game three's 5-1 win. That game might have been a blowout victory with a semblance of improved RISP hitting.

It's a problem that the Diamondbacks only had 12 at-bats with runners in scoring position. It's a worse problem only one resulted in a hit. This will have to change very quickly.

Early deficits vs early leads

Jun 7, 2026; Phoenix, Arizona, USA; Arizona Diamondbacks right fielder Corbin Carroll (7) celebrates his solo home run during the first inning at Chase Field. Mandatory Credit: Arianna Grainey-Imagn Images | Arianna Grainey-Imagn Images

The Diamondbacks are a team who frequently find ways to rally from large deficits. It's been a part of their identity for some time.

With that said, games one and two of their series against Washington felt over before they began. Both Eduardo Rodriguez and Merrill Kelly, without recording an out, allowed the leadoff hitter to reach, and served up a two-run homer in the first inning.

In both losses, the Diamondbacks were set up with deficits before their offense had a chance to get any work in.

Not only did it set the tone for the pitching staff, as both games spiraled into uglier pitching performances, but early deficits can also alter the outlook from an offensive perspective.

The only game in which Arizona did not face a deficit before the second inning was game three — the only game the Diamondbacks came out of victorious.

Big question remaining after Diamondbacks' loss to Nationals

Is regression hitting Diamondbacks' starting pitching?

Jun 5, 2026; Phoenix, Arizona, USA; Arizona Diamondbacks pitcher Merrill Kelly (29) throws against against the Washington Nationals during the first inning at Chase Field. Mandatory Credit: Arianna Grainey-Imagn Images | Arianna Grainey-Imagn Images

The Diamondbacks starting rotation had been one of the better units in baseball coming in to this series — even considering some less-than-perfect outings against the Dodgers.

However, Arizona's starters looked notably less effective in games one and two of this series. Kelly was crushed for seven earned runs in five innings after posting a 2.36 ERA across his previous five starts. Rodriguez gave up more than three runs (four) for the first time since April 22.

Michael Soroka did not join those ranks. He threw seven innings of one-run baseball in Arizona's lone win.

The question is whether or not true regression is hitting the D-backs' starters, or if they simply ran into a very strong Nationals offense. Rodriguez's expected ERA of 4.61 is over two runs higher than his 2.52 ERA. Kelly's xERA is 7.63.

The main concern is that these results are more closely aligned with how well each arm has pitched, and similar results could continue going forward. But you can't predict baseball.