Senzel was considered to be one of the best available players in the 2016 Major League Baseball draft, The Philadelphia Phillies, who had the first overall pick, scouted Senzel. Many baseball executives and scouts agreed that Senzel was the safest pick in the draft. He was also rated as the best hitter in the draft because of his abilities to hit gap-to-gap with power. After the Phillies selected Mickey Moniak with the first overall selection, the Cincinnati Reds chose Senzel with the second overall pick. On June 13, 2016, Senzel signed with the Reds, receiving a $6.2 million signing bonus. Senzel made his professional debut with the Billings Mustangs of the Rookie-levelPioneer League, where he batted.152 with one double. He was promoted to the Dayton Dragons of the Class AMidwest League on June 30. He hit.329 with seven home runs for Dayton. Senzel began the 2017 season with the Daytona Tortugas of the Class A-AdvancedFlorida State League, and was promoted to the Pensacola Blue Wahoos of the Class AASouthern League in June. He posted a combined.321 batting average with 14 home runs, 65 RBIs, and a.905 OPS in 119 games between Daytona and Pensacola. Senzel began 2018 with the Louisville Bats of the Class AAAInternational League. On June 23, 2018, it was revealed that Senzel's 2018 season ended after he required surgery to repair a torn ligament on his right index finger. Upon his return from injury, Senzel told new Reds' manager David Bell, that he was preparing to play center field. The Reds allowed Senzel to play center field in Spring Training with a chance to compete with Scott Schebler for the starting role. He had a.308 with a.300 on-base percentage and a.462 slugging percentage. Despite his performance, the Reds elected to send Senzel to minor league camp. Senzel's agent assumed that the service-time rules in baseball was the majority influence on the team's decision; if Senzel were to play 12 days in the minors before being promoted to the majors, the Reds would receive another year of club control. Just three days later, Senzel sprained his ankle during a minor league game. In eight games with Louisville, Senzel hit one home run and batted.257.
Cincinnati Reds
On May 3, 2019, Senzel was called up to the majors by the Reds. He made his major league debut that day at Great American Ballpark, going 1-for-5 two strikeouts and two walks. Senzel's first hit was a slow-roller to third that he beat out off the San Francisco Giants' Tony Watson. Senzel hit his first major league home run on May 4, off Giants' Dereck Rodríguez. His second and third home runs came two days later at home against the Giants off Drew Pomeranz. Senzel finished the month of May with a.279 batting average, four home runs, 12 RBIs, and 12 walks. On September 12, 2019, Senzel was placed on the injured list with a torn labrum. In 104 games of his first season in the Majors, Senzel batted.256 with 12 home runs, 20 doubles, and 42 RBIs.