BOSTON – (Staff Report from Official News Release) – The Boston Red Sox acquired left-handed pitcher Erik Miller and minor league outfielder Carlos Gutierrez from the San Francisco Giants, in exchange for infielder Marcelo Mayer.
Miller, 28, has made 38 appearances for the Giants this season, going 2-0 with 10 holds, four saves, a 2.76 ERA (10 ER/32.2 IP), and 45 strikeouts. The left-hander ranks in MLB’s 90th percentile or higher in average exit velocity (99th, 83.1 MPH), expected batting average (98th, .181), hard-hit rate (98th, 27.4%), whiff rate (97th, 34.8%), strikeout rate (95th, 31.7%), and groundball rate (92nd, 53.4%). He has made 14 consecutive scoreless appearances, beginning on June 19, tossing 13.0 innings over that span while recording a 0.85 WHIP and .143 opponent batting average (6-for-42).
Originally selected by the Philadelphia Phillies in the fourth round of the 2019 First-Year Player Draft, the Missouri native owns a 3.05 ERA (44 ER/130.0 IP), a .210 opponent batting average (97-for-461), and 154 strikeouts in 147 career games (10 starts) with the Giants (2024-26). In his career, he has held left-handed hitters to a .189 batting average (35-for-185) and .550 OPS.
Gutierrez, 21, is ranked by Baseball America as the Giants’ No. 24 prospect. The left-handed hitter has played in 83 games for High-A Eugene this season, batting .271 (81-for-299) with an .826 OPS, 18 doubles, three triples, nine home runs, 45 RBI, and 26 stolen bases while making 64 starts in left field, 18 as the designated hitter, and one in center field. Signed by San Francisco as an international free agent in January 2023, the Mexico native has hit .314 (200-for-637) with 33 doubles, nine triples, 12 home runs, 85 RBI, 64 stolen bases, and an .866 OPS in 168 career minor league games, all in the Giants’ organization.
Mayer, 23, has played in 70 games for Boston this season, hitting .220 (45-for-205) with 19 runs scored, 10 doubles, three home runs, and 22 RBI while making 39 starts at second base and 20 at shortstop. The left-handed hitter was placed on the 10-Day Injured List on June 26 with a bone stress reaction to the left ulna. Selected by the Red Sox in the first round (No. 4 overall) of the 2021 First-Year Player Draft, the California native has hit .223 (74-for-332) in 114 career Major League games, all with Boston (2025-26).