He has previously played in MLB for the Tampa Bay Rays, Miami Marlins, Houston Astros, and Seattle Mariners.

[9] Stanek was considered one of the top available prospects in the 2013 MLB Draft,[10] and was selected by the Tampa Bay Rays with the 29th pick in the first round.

[11] He did not pitch professionally immediately after he signed, as he had surgery on his right acetabular labrum during the 2013–14 offseason, which led to him missing the start of the 2014 season.

[13] After pitching to a 3–4 record and a 3.63 ERA for Bowling Green, the Rays promoted Stanek to the Charlotte Stone Crabs of the Class A-Advanced Florida State League in July.

[14] Stanek began the 2015 season with Charlotte, and was later promoted to the Montgomery Biscuits of the Double-A Southern League.

[20] In a similar vein, Stanek set a major league record with 17 straight starts allowing one run or fewer.

[22] For the majority of the season, Stanek was used as one of the Rays' "opening" starters, making 59 total appearances (29 starts).

On July 31, 2019, the Rays traded Stanek and Jesús Sánchez to the Miami Marlins in exchange for pitchers Nick Anderson and Trevor Richards.

[30] He earned his first save of the season on April 27 versus the Texas Rangers, allowing one run one in the ninth and leaving runners stranded on second and third to close out a 4–3 win.

[32] Stanek produced 10 straight scoreless appearances until September 25, when the Baltimore Orioles scored a run in the eighth inning.

[33] In the 2022 season finale versus the Philadelphia Phillies, Stanek pitched a clean seventh to lower his ERA to 1.15, eclipsing the single-season franchise record for relievers set by Will Harris in 2019.

[36] On January 13, 2023, Stanek agreed to a one-year, $3.6 million contract with the Astros, avoiding salary arbitration.

On July 26, 2024, the Mariners traded Stanek to the New York Mets in exchange for minor league prospect Rhylan Thomas.

[39] Stanek had a poor debut for the Mets, allowing three runs in the 7th inning to the Atlanta Braves on July 28.