SAN FRANCISCO — The Mets’ big focus before the July 31 trade deadline has been relief pitching, and all the better if one piece added is left-handed.

To that end, the team found a match on Friday, acquiring lefty reliever Gregory Soto from the Orioles for minor league pitchers Wellington Aracena and Cameron Foster.

The Mets officially announced the trade hours before the team opened a weekend series against the Giants with an 8-1 win.

Soto, 30, owns a 3.96 ERA in 45 appearances this season with 44 strikeouts in 36 ¹/₃ innings.

Among his favorable metrics are a 4.3 barrel percentage (which ranks in MLB’s 94th percentile, according to Statcast) and 31.1 whiff percentage that ranks in the 87th percentile.

Soto, twice an All-Star with the Tigers, has retired all 23 left-handed batters he’s faced since June 4, with 14 strikeouts.

“It’s a big arm,” president of baseball operations David Stearns said. “He’s pitched in leverage spots. We were looking to help complement our bullpen from the left side. It’s not always easy to do that this time of year, so as we began to overlap with some names with Baltimore we figured this was the time to push this one through.”

The Mets received a boost in lefty relief immediately following the All-Star break with Brooks Raley’s return from the injured list following Tommy John surgery rehab.

A.J. Minter and Danny Young began the season as the Mets’ two lefty bullpen options, but both were lost to surgery and won’t return this year.

Before Raley’s return, the team had used a rotating cast in lefty relief that included Génesis Cabrera, José Castillo and Richard Lovelady.

Aracena, 20, pitched to a 2.38 ERA in 17 appearances this season for Single-A St. Lucie.

He was the Mets’ No. 20 prospect, according to MLB Pipeline.

Foster, 26, has pitched for Double-A Binghamton and Triple-A Syracuse, with a 2.97 ERA in 21 appearances.

He was selected by the Mets in the 14th round of the 2022 draft.

Ideally, the Mets would like to add another reliever before Thursday’s deadline.

“We’re still talking,” Stearns said. “I think there’s still the ability to upgrade our bullpen. We’re not going to close the door to it.”

Team officials are also on the lookout for a potential rotation addition, but asking prices remain steep for the handful of pitchers available that would be considered an upgrade for the Mets.

And Stearns indicated an addition would be with the idea of raising the rotation’s ceiling rather than just adding depth.

The possible names available include former Cy Young award winner Sandy Alcantara, who has struggled in his comeback season from Tommy John surgery.

The Mets have checked in with the Marlins on the right-hander, according to a source, but the asking price in terms of prospects is high.

“You don’t know what’s going to be available and ultimately what is going to be traded — acquiring starting pitching at this time of year is pretty difficult,” Stearns said. “I don’t know how many raise the ceiling type players are going to be available in that segment, but if those guys are available we’ll be involved.”

The Mets are keeping tabs on potential available outfielders with an eye toward upgrading center field.

But team officials also have no sense of urgency on that front given Jeff McNeil’s play at the position in a job share with defensive whiz Tyrone Taylor.

If the Mets were to trade from their major league roster, Brett Baty, Ronny Mauricio, Luisangel Acuña and Mark Vientos are available.

That said, the team isn’t in any hurry to part with any member of that quartet. Baty, in particular, has emerged lately at third base.

The Mets have received inquiries about Starling Marte, according to a source.

The veteran outfielder — in the final months of his four-year contract worth $78 million — has provided a productive right-handed bat for the club, but overlaps with Vientos for DH at-bats.

Even so, Marte’s clubhouse presence and experience are valued by the team.