WASHINGTON — Help is on the way at first base for the Yankees, in the form of Anthony Rizzo, potentially as soon as this weekend.

In the meantime, DJ LeMahieu started his fourth straight game at the position as the Yankees faced their fourth straight left-handed starter in Wednesday’s 5-2 loss to the Nationals.

The struggling veteran went 5-for-13 with a pair of sacrifice flies during the four-game stretch, but his 1-for-3 Wednesday night included grounding into an inning-ending double play to squash a rally before being pinch-hit for by Oswaldo Cabrera in a ninth-inning rally.

On the whole this year, LeMahieu has been a shell of himself after starting the season late to deal with a non-displaced foot fracture.

The 36-year-old, who still has two years and $30 million left on his contract after this season, finished Wednesday batting .202 with a .526 OPS across 225 plate appearances.

“His season’s been a little different in that — obviously the track record matters,” manager Aaron Boone said before the game when asked at what point the results mattered for LeMahieu in terms of continuing to start against lefties. “Obviously behind the eight ball a little bit from an injury standpoint to start the year. So you want to let things really declare themselves to where you’re making sound decisions moving forward.”

Meanwhile, Rizzo started a second straight rehab game at first base Wednesday for Double-A Somerset — striking out twice before the game was suspended by rain in the bottom of the fifth — and the plan was for him to return to New York on Thursday for the Yankees to reevaluate his status.

Boone was noncommittal when asked if Rizzo could be in play this weekend against the Cardinals, who are set to start three right-handed pitchers.

Initially, the plan was for Rizzo to not play first base until this weekend, after strictly DHing to start his rehab assignment, but he got further tests recently that led to doctors clearing him for action in the field.

Boone mentioned planning to start Ben Rice at first base Friday against Cardinals righty Erick Fedde, though the rookie is expected to be optioned to Triple-A whenever Rizzo comes back.

Clarke Schmidt (lat strain) made his second rehab start Wednesday night, this one for Triple-A Scranton/Wilkes-Barre, building up to 58 pitches while striking out five and giving up one run across three innings.

Boone said Schmidt would “probably” make at least one more rehab start (presumably next Tuesday) before potentially rejoining the team.

Luis Gil (lower back strain), meanwhile, came out of Tuesday’s live batting practice session well and is in line to make a rehab start, likely Sunday — setting him up to return Sept. 6 against the Cubs if all goes well.

In the meantime, Will Warren is scheduled to make another spot start for Gil on Saturday against the Cardinals in The Bronx.

Lou Trivino (UCL surgery) and Ian Hamilton (lat strain) have yet to pitch in back-to-back games during their respective rehab assignments, but Boone said that was not necessarily a requirement before the Yankees would activate them.

As for fellow reliever Scott Effross, who is done with his rehab assignment but still knocking off some rust from Tommy John and back surgery?

“I think he’s been doing a pretty good job now for really a couple weeks, the stuff’s trending up,” Boone said. “So he’s knocking on the door.”