The San Francisco Giants had an off day on Thursday after losing two out of three games to the Houston Astros.
Meanwhile, the Giants’ Triple-A affiliate, the Sacramento River Cats, played the Las Vegas Aviators on Thursday night.
It was the first game of Marcelo Mayer’s rehab assignment. It did not take long for the former top prospect to introduce himself to the Giants.
Marcelo Mayer’s Performance in Giants Minor League Debut
The former fourth overall pick was acquired by the Giants at this year’s MLB trade deadline. San Francisco sent left-handed reliever Erik Miller and minor leaguer Carlos Gutierrez to the Boston Red Sox.
The Giants sent Mayer to Triple-A for a rehab assignment before he joins the big league club. The infielder is returning from a left ulna (forearm) stress reaction injury that he suffered in late June. He last played for the Boston Red Sox on Jun. 25.
Mayer was the starting second baseman and leadoff hitter in his first game with the Rivercats.
The 23-year-old hit a solo home run in his second at-bat with the Giants’ organization.
Mayer sends one dead center to give us the lead!
Mayer finished 1-for-2 with a walk in his organizational debut. The once-top prospect showcased his upside and could be a compelling part of the San Francisco Giants’ future.
GettyBOSTON, MASSACHUSETTS – JUNE 16: Marcelo Mayer #11 of the Boston Red Sox throws the ball to first for an out in the first inning against the Toronto Blue Jays at Fenway Park on June 16, 2026 in Boston, Massachusetts. (Photo by Jaiden Tripi/Getty Images)
Marcelo Mayer Could Join the Giants’ Lineup Soon
It is already a good sign that Mayer is starting and playing well in his first rehab game.
“Marcelo Mayer is playing second base for the River Cats tonight. Giants don’t think he’ll need many rehab games before he’s in big league lineup,” according to Alex Pavlovic of NBC Sports Bay Area.
After veteran shortstop Willy Adames left Wednesday’s game against the Astros, the Giants need middle infield help. San Francisco also traded Luis Arraez during the deadline, leaving second base open.
Mayer has experience at shortstop at the big league level. He played 24 games at the position with the Red Sox earlier this season. He also played 45 games at second base for Boston this year.
GettyAfter the Boston Red Sox traded Marcelo Mayer to the San Francisco Giants, he’s ready for a fresh start with a new team.
Social Media Reactions To Marcelo Mayer’s Home Run
Giants fans took to social media to share their reactions to Mayer’s home run:
Even Year Dynasty Show: “Welcome to the Giants org Marcelo Mayer! He homers in his 2nd rehab AB!”
Coast to Coast Baseball: “Marcelo Mayer with an absolute laser beam of a HR to CF in his first rehab game Cannot wait to watch him in San Francisco, that swing is pretty man.”
@GiantsCursed: “Whatever, being me Marcelo Mayer, what’s the worst that can happen? He wins the vacant 2B job?”
Marcelo is King: “Future MVP Marcelo Mayer hits his first homerun for the SF organization.”
Giants’ Trade Acquisition Marcelo Mayer Shines In Organizational Debut