The San Francisco Giants acquired infielder Marcelo Mayer from the Boston Red Sox just before the 2026 MLB trade deadline on Monday, according to Joel Sherman of the New York Post. 4 overall pick in the 2021 MLB draft will be experiencing a change of scenery for the first time in his career. Mayer's potential was high upon making his Red Sox debut, as he was listed as the No. As for the Red Sox, they obtained Miller as they look to make a postseason run. The 28-year-old owns a 2.76 ERA in 38 games this season, racking up 45 strikeouts in 32.2 innings of work.