WASHINGTON -- Tyler Austin made his return to the Giants’ lineup in Thursday's 4-2 loss to the Nationals, starting at first and going 1-for-4 with a run scored after missing four games because of right elbow soreness. But lingering concerns remain that are keeping Austin out of the defensive position San Francisco prefers.

“He hasn’t been able to do some more work in left field,” manager Bruce Bochy said. “Once we get to Pittsburgh, we’ll resume his work out there.”

Acquired in a trade from the Twins on April 8 to try to add some needed power-hitting depth, the Giants want Austin in left because it allows Brandon Belt to remain at first, where Belt is a plus defender.

Belt started in left for the third time this season on Thursday, and he went 0-for-3 with two strikeouts before getting ejected in the seventh inning for arguing balls and strikes.

Posey playing three?

Bochy also said he feels Buster Posey is approaching the point where he can play as often as he has in previous seasons, and he could even start all three games of San Francisco’s upcoming series in Pittsburgh.

Posey has played in 16 of the Giants’ first 19 games this year, making 13 starts at catcher and two at first base as he works back to 100 percent following surgery to repair a right hip impingement and torn labrum last August.

Posey was out of San Francisco’s lineup on Thursday in a day game after a night game, but he was available off the bench.

“There’s nothing holding him back now,” Bochy said. “He isn’t getting a day because it’s gotten really cranky.”

No triples alley in Washington

Rookie outfielder Steven Duggar homered in back-to-back games for the first time in his career on Tuesday and Wednesday, showing off a potential added dimension to the leadoff man’s game.

Well, sort of.

The left-handed Duggar pulled his shot 408 feet to right-center on Wednesday, and as Giants fans know well, that may not have even reached the warning track in Oracle Park’s Triples Alley.

All the more reason for the former Clemson man, who has never hit more than 10 home runs in a Minor League season, to keep his focus on driving the ball to the opposite field.

“For me, the objective is just to find a way on base,” Duggar said. “When I put my A-swing on it, sometimes it might end up leaving.”