Spencer Ketcham Turnbull (born September 18, 1992) is an American professional baseball pitcher who is a free agent.

Turnbull played college baseball for the Alabama Crimson Tide before the Tigers selected him in the second round of the 2014 MLB draft.

[10] He made his major league debut on September 14, pitching a 1-2-3 inning of relief with one strikeout against the Cleveland Indians.

In 2019, Turnbull made the starting rotation out of spring training and earned his first MLB win on April 23.

[13] Turnbull started 11 of the Tigers' 58 games during the 2020 season, compiling a 4–4 record with a 3.97 ERA and 51 strikeouts in 58+2⁄3 innings.

Turnbull did not make the Tigers' Opening Day roster for the 2021 season, due to being placed on the non-baseball related (COVID-19) injured list.

[15] On May 18, 2021, Turnbull pitched the eighth no-hitter in Tigers history against the Seattle Mariners, recording nine strikeouts and two walks in a 5–0 win.

Turnbull returned to major leagues on April 2, 2023, allowing seven runs on eight hits and three walks in 2+1⁄3 innings against the Tampa Bay Rays.

[25] He made his first appearance and start with the Phillies on April 2, where he threw five innings and allowed three hits, no earned runs, no walks, and seven strikeouts.