​ATLANTA, GEORGIA – MAY 16: Marcelo Mayer #11 of the Boston Red Sox bats in the ninth inning against the Atlanta Braves at Truist Park on May 16, 2026 in Atlanta, Georgia. (Photo by Kevin C. Cox/Getty Images) GettyThe San Francisco Giants are close to a deal with the Boston Red Sox, per The Athletic‘s Andrew Baggarly and Ken Rosenthal. The deal will send left-hander Erik Miller to Boston in exchange for former Red Sox top prospect Marcelo Mayer.Giants close to acquiring Marcelo Mayer from Red Sox for reliever Erik Miller, sources tell me and Andrew Baggarly.— Ken Rosenthal (@Ken_Rosenthal) August 3, 2026The Giants are selling high on Miller, who has a 3.05 career ERA in 147 appearances. That’s allowed them to land a potential impact player in a trade.This trade represents a buy-low opportunity for the Giants on a former top prospect. Mayer was selected fourth overall by Boston in the 2021 MLB Draft and debuted with the club in 2025.However, Mayer’s bat hasn’t translated to consistent MLB production yet. In 114 career games, he has a .223/.278/.346 slash line with seven home runs and a 69 wRC+. Much of that track record comes in 2026, where he’s hitting .220 with a .594 OPS in 70 games.While things didn’t work out in Boston, the 23-year-old will get a fresh start in San Francisco. He’s currently with the Red Sox’s Triple-A affiliate in Worcester at the time of trade.Giants Acquire Marcelo Mayer in Deadline Deal with Red SoxThe Giants have an opening on their infield after dealing All-Star second baseman Luis Arraez to the Philadelphia Phillies. With an obvious hole in their infield, the club sought a longer-term solution.Mayer is controllable through the 2032 season, giving San Francisco a long-term upside play at a middle infield spot. He immediately slots in at the second base spot.The 23-year-old has pretty decent tools. He clocks in at a 74.6 MPH bat speed, which ranks well, and a solid chase rate of 29.2%. However, the key for the Giants will be getting more pulled contact in the air. Mayer has just a 9.7% air pull rate on contact, which is not conducive to a higher slugging percentage.The Giants were also hoping to shed some of their larger contracts. They ultimately did not find many takers for Matt Chapman, Willy Adames, or Rafael Devers. All three players are owed more than $100 million over the remainder of their contracts.For the rest of the season, the Giants can afford to try out Mayer at second base and see where he fits long-term. If the experiment doesn’t work out, the club could always turn to 2026 breakout hitter Casey Schmitt to fill the role once he recovers from a meniscus tear.Giants Firesale Continues at the DeadlineThe Giants have been very busy in the final hours ahead of the trade deadline. The club has dealt Luis Arraez, Caleb Killian, Robbie Ray, Heliot Ramos, and Erik Miller for prospects and young players.Here’s a recap of the players they’ve gotten at the deadline:Phillies: RHP Ramon Marquez