Giants trade Mike Yastrzemski to the Royals

Mike Yastrzemski was traded to Kansas City in the final minutes before the trade deadline for Single-A pitching prospect Yunior Marte.

One day after he made the most spectacular catch of the season, the San Francisco Giants traded longtime outfielder Mike Yastrzemski to the Kansas City Royals. In return, the Giants are getting right-handed pitching prospect Yunior Marte, a 21 year old from the Dominican Republic. Marte has spent the year in Single-A where, in 82 starts, he has a 2.74 ERA and a 3.01 FIP. Fangraphs ranked him as the No. 12 prospect in Kansas City’s system, while MLB Pipeline had him at No. 20.

Buster Posey and the Giants front office are waving the white flag after a miserable 2-10 start to the second half. After already trading top relievers Tyler Rogers and Camilo Doval, the Giants are parting ways with Mike Yastrzemski, a huge part of their team for the last seven seasons and one of the stars of their 107-win team in 2021. In return, they’ll receive Yunior Marte, a 21-year-old minor-league starter currently pitching for the Single-A Columbia Fireflies.

Yastrzemski didn’t reach the majors until he was 28 years old, but he became a key figure for the Giants, playing 790 games and finishing 8th in the MVP voting in the shortened 2020 season. The Giants got him from the Baltimore Orioles for minor-league reliever Tyler Herb, after Yastrzemski’s impressive minor league career, which included multiple All-Star appearances but also some untimely injuries.

The grandson of Hall of Famer Carl Yastrzemski, “Yaz” won the Willie Mac Award for the most inspirational Giant in 2020, a year where he slashed .297/.400/.568 and tied for the league lead in triples. He had the best range factor per nine innings for all right fielders in 2020 and 2021, rarely hitting for average but delivering plate discipline and solid power.

Despite his family pedigree, it took Yastrzemski nearly six years to get a crack at the majors after the Orioles made him a 14th-round pick out of Vanderbilt. Like the departed Tyler Rogers, Yaz was essentially a minor-league journeyman who capitalized on his opportunity to become a crucial and memorable part of the Giants for six-plus seasons.

In what proved to be his final games as a Giant Wednesday, Yaz made a dramatic catch, leaping over a wall and sacrificing his body to steal an out for the Giants. It was a nice cap on a Giants career where he was always one of the best defensive right fielders in baseball.

Yastrzemski wasn’t hitting as well in 2025, slashing .231/.330/.355, mainly because he’s been miserable against left-handed pitching (.145/.181/.217 in 73 plate appearances). That will be less of an issue in Kansas City, where the Royals also traded for a ready-made platoon partner for Yaz, right-handed hitting Randall Grichuk.

This deal will seemingly open a path to more playing time for Luis Matos, or the promotion of a player like Wade Meckler, Grant McCray, or Marco Luciano. Or possibly newcomer Drew Gilbert, who was acquired in the Rogers deal.

Marte should not be confused with the Yunior Marte who appeared in 39 games for the 2022 Giants. This Marte is 6-foot-5 and 210 pounds, currently getting his first extended playing time after a few injury-marred season since the Royals signed him in 2022. He’s started 19 games for the Fireflies with a 2.74 ERA and 79 strikeouts in 82 innings.

MLB.com ranked him the Royals’ No. 20 prospect before the season, though his success in Single-A may have moved him up the list. He was the Carolina League’s Pitcher of the Month in May. Marte’s repertoire includes a 92-95 MPH fastball, an 85-87 MPH slider, and a changeup that’s said to be improving. He’s probably not reaching the major leagues before 2027.

While it’s not a shock that the Giants would move Yastrzemski to a playoff aspirant, given his impending free agency and $9.25M salary, it’s another dramatic sign that the Posey-led Giants are willing to commit to selling off veterans at the deadline, whether they have 114 home runs in a Giants uniform or not.