Sadzeck made his professional debut in 2012 with the Spokane Indians and he spent the whole season there, going 1–4 with a 4.06 earned run average (ERA) in 15 games. He spent 2013 with the Hickory Crawdads where he compiled a 12–4 record, 2.25 ERA, and a 1.16 WHIP in 24 starts. He missed the 2014 season after undergoing Tommy John surgery.[2] Sadzeck spent 2015 with both the High Desert Mavericks and Frisco RoughRiders, posting a combined 3–2 record and 5.82 ERA in 60.1 innings pitched.
The Rangers added him to their 40-man roster after the 2015 season.[3] In 2016, he played for Frisco where he was 10–8 with a 4.16 ERA in 25 games (23 starts), and in 2017, he once again pitched for Frisco, going 4–8 with a 6.25 ERA in 38 games (13 starts).[4] He spent the 2018 minor league season with the Round Rock Express, going 5–3 with a 4.03 ERA in 38 innings.
Texas Rangers
Sadzeck made his MLB debut on September 1, 2018.[5] He pitched in 13 major league games in 2018, posting a 0.96 ERA, 7 strikeouts, and 11 walks in 9 innings. Sadzeck used his third and final minor league option during the 2018 season.[6] On March 28, 2019, he was designated for assignment by the Rangers.[7]
On April 1, 2019, Sadzeck was traded to the Seattle Mariners in exchange for Grant Anderson.[8] He was outrighted off of the Mariners roster on October 28.[9]
Chicago White Sox
On February 25, 2020, Sadzeck signed a minor league deal with the Chicago White Sox. He was released on August 3, 2021 after he played in 23 games for the Triple-A Charlotte Knights and was 2–2 with a 5.86 ERA.
Milwaukee Brewers
On August 11, 2021 Sadzeck signed a minor league deal with the Milwaukee Brewers. He was assigned to the Triple-A Nashville Sounds.[10] On July 13, 2022, Sadzeck was selected by the Brewers. On July 25, 2022, Sadzeck was designated for assignment. On July 30, 2022, Sadzeck elected free agency.
Washington Nationals
On August 4, 2022, Sadzeck signed a minor league deal with the Washington Nationals.[11] Sadzeck pitched in 17 games for the Triple-A Rochester Red Wings, posting an 0-3 record and 3.86 ERA with 21 strikeouts in 21.0 innings of work. He elected free agency following the season on November 10.[12]
Minnesota Twins
On February 10, 2023, Sadzeck signed a minor league contract with the Minnesota Twins organization.[13] In 25 games for the Triple–A St. Paul Saints, he recorded a 5.40 ERA with 42 strikeouts and 1 save in 35.0 innings of work. Sadzeck was released by the Twins on July 5.[14]
Pittsburgh Pirates
On February 2, 2024, Sadzeck signed a minor league contract with the Pittsburgh Pirates.[15]