Marco Elias Gonzales (born February 16, 1992) is an American professional baseball pitcher who is a free agent.

He has previously played in Major League Baseball (MLB) for the St. Louis Cardinals, Seattle Mariners and Pittsburgh Pirates.

He made his MLB debut in 2014, and underwent Tommy John surgery in 2016 for a torn ulnar collateral ligament in his left elbow.

As a senior, he was named the Colorado High School Baseball Player of the Year after compiling an 11–0 won–loss record (W–L) with a 2.20 earned run average (ERA) and 87 strikeouts (SO) in 54 innings pitched (IP).

[2] He started the Class 5A state championship game for Rocky Mountain in all four years of his high school career, winning all four.

[12] Gonzales began the 2014 season with Palm Beach, and received a promotion to the Springfield Cardinals of the Double–A Texas League in May.

The Cardinals called him up to the major leagues, and, the day before he made his MLB debut, he was named to the 2014 All-Star Futures Game at Target Field in Minneapolis, Minnesota.

[14][15] Filling in for the injured Jaime García, Gonzales made his major league debut as the starter against the Colorado Rockies on June 25.

Gonzales began with three scoreless innings, but got into trouble in the fourth by giving up a lead-off home run to Drew Stubbs, two doubles and two singles.

[18] Gonzales became the first Cardinals' starter to make his debut without playing at the Triple A level since Cliff Politte in April 1998.

The outing went similar to his first MLB appearance, he started with three scoreless innings but yielded multiple runs in the fourth.

[20] After posting a 7.07 ERA in first three MLB starts, the Cardinals optioned him to the Triple-A Memphis Redbirds on July 7, where he appeared for the first time.

[23] He made 10 total MLB appearances, five as a starter, completing 34+2⁄3 IP, allowing 32 H, 21 BB, 16 ER and a 4.15 ERA with a 4–2 W–L.

He recorded three total scoreless innings in the National League Division Series (NLDS) against the Los Angeles Dodgers.

[26] He pitched another three innings against the Giants in the National League Championship Series (NLCS), giving up three earned runs as the Cardinals were eliminated from the postseason.

[25] Having struggled with a shoulder injury for much of the 2015 season, Gonzales totaled 13 starts and 64 innings with Memphis, allowing a 5.20 ERA with 81 hits and a .315 batting average against.

[27] He made his first major league appearance and start of the season against the Washington Nationals that day, allowing four runs in less than three innings.

[33] Gonzales made his Mariners debut on August 6, 2017 against the Kansas City Royals, in which he went 4 innings, allowing 5 earned runs on 7 hits, a walk, and 5 strikeouts.

[34] In 2017 with the Mariners, he made 7 starts (10 appearances total), going 1–1 with a 5.40 ERA (22 earned runs) and 4.28 FIP with 30 strikeouts and 11 walks.

[36] On June 29, he threw his first career complete game against the Kansas City Royals, limiting them to just 1 run on 6 hits, 7 strikeouts, and no walks.

[38] Nonetheless, Gonzales managed to stay healthy in his first full season in Seattle, starting a career-high 29 games, leading the team in wins with 13 while striking out 145 batters and compiling a 4.00 ERA and 3.43 FIP over 166.2 innings pitched.

[55] On December 3, 2023, the Mariners traded Gonzales, Jarred Kelenic, and Evan White to the Atlanta Braves for Jackson Kowar and Cole Phillips.

[57] Gonzales began the 2024 season in Pittsburgh's rotation, making 3 starts and posting a 2.65 ERA with 11 strikeouts across 17 innings pitched.

In 7 total appearances on the season for Pittsburgh, Gonzales logged a 1–1 record and 4.54 ERA with 23 strikeouts over 33+2⁄3 innings pitched.