ARLINGTON — Luis Arraez didn’t need much time to become a fan favorite in San Francisco. Now, he’ll be taking his talents back to the NL East.

The Giants have traded Arraez and reliever Caleb Kilian to the Philadelphia Phillies in exchange for right-handed pitchers Ramon Marquez and Marty Gair, the team confirmed Monday morning.

This is San Francisco’s second trade ahead of Monday’s 3 p.m. PT deadline, having sent right-hander Tyler Mahle to the Atlanta Braves on Sunday evening.

Marquez, 20, is the Phillies’ No. 4 prospect per Baseball America, and this news organization recently reported that the Giants had a scout in attendance for one of his recent outings.

The right-hander has been phenomenal this season, with a 1.68 ERA and 93 strikeouts over 59 innings. He instantly becomes one of the best pitching prospects in their farm system. Marquez’s best offering is a changeup, which one member of the organization assessed a 70-grade on the 20-80 scouting scale. Similar to Luis Hernandez, the Giants’ No. 2 prospect, Marquez skipped the Dominican Summer League.

Gair, 23, was selected in the 13th round of the 2023 MLB draft and has posted a 4.50 ERA and 3.88 FIP over 36 innings with 66 strikeouts this season. The right-hander missed the 2024 season due to an elbow injury and has dealt with command issues, but one team source said the team is high on his upside. His fastball sits in the high 90s and has touched as high as 102 mph.

Marquez and Gair are the latest additions to a farm system that recently beefed up its pitching depth after adding right-hander Jackson Flora with the fourth overall pick in the 2026 MLB draft, as well as prep pitchers Carson Bolemon (No. 29) and Kaden Waechter (No. 55) with its second and third selections.

San Francisco signed Arraez to a one-year, $12 million deal right before spring training with the intention of letting him play second base, a decision met with curiosity because of Arraez’s reputation as a poor defender. Plus, Arraez was coming off two down years in 2024 and 2025 in which he was barely above league average as a hitter.

Despite those valid concerns, Arraez played some of the most complete baseball of his career en route to earning his fourth career All-Star appearance. At the plate, his .324 batting average is the second-best in the majors. With the glove, his +11 outs above average (a range-based defensive stat) are the second-most among all second basemen.

Arraez said he was willing to sign an extension, but with Rafael Devers, Willy Adames, Matt Chapman and Jung Hoo Lee already on long-term contracts, adding another deal to the books didn’t appear to be tenable.

In being traded to the Phillies, Arraez can still qualify for the NL batting title. If he wins, it would be his fourth batting title with a fourth different team.

Casey Schmitt was positioned to take over as the Giants’ starting second baseman, but he’s currently on the injured list after tearing his left meniscus on July 28 and might miss the remainder of the season.

Schmitt, 27, was in the midst of a career year, having already reached career highs in homers (21), RBIs (55) and steals (nine). He’s bounced all around the diamond, spending time at first base, second base, third base, shortstop and left field, and the Arraez trade would’ve provided him with an opportunity to settle into one position for the first time all season. Following the injury, that option is no longer available.

Even with Arraez’s departure and Schmitt’s trade, the Giants have options who could see time at second base over the final two months.

Oslievis Basabe has made noise in recent days by hitting two home runs in the Giants’ last two games, but he left Sunday’s game after taking a 100.8 mph pitch to the left elbow. Rookie Nate Furman, who had a .370 on-base percentage with Triple-A Sacramento, was recently called up. Christian Koss is a natural infielder and played excellent defense at second base last season (+8 defensive runs saved)

Rookie Jesús Rodríguez was another possibility to get some run, but he recently landed on the 10-day injured list with right elbow neuritis. Rodríguez is capable of catching along with playing infield and outfield, but the 24-year-old hasn’t had many opportunities to get consistent at-bats in the majors.

Another intriguing possibility is fellow rookie outfielder Jonah Cox, who played middle infield in college. Cox has only played a handful of professional innings at second base but has looked like a natural, making several impressive plays despite getting limited reps.

Kilian, 29, signed a minor league deal with the Giants this offseason and worked his way into being the team’s closer for a good chunk of this season, though he was inconsistent in that role. Over 44 1/3 innings, Kilian posted a 4.26 ERA and 3.59 FIP while striking out 53 batters and projects to pitch in a setup role for Philadelphia.

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