He was a part of their minor league system before making his MLB debut in 2022, becoming a consistent member of their lineup as a utility player.

[5] He signed with St. Louis and made his professional debut with the State College Spikes of the Class A Short Season New York–Penn League, playing in four games.

[12] He made his MLB debut that night against the New York Mets as a pinch runner and scored on a single by Tyler O'Neill.

[14] On April 28, 2022, Donovan recorded his first career hit: a pinch-hit single against fellow rookie Tyler Holton of the Arizona Diamondbacks.

[18] He was named a finalist for the National League Rookie of the Year Award, alongside Michael Harris II and Spencer Strider.

On August 2, 2023, it was announced that Donovan would undergo season–ending surgery to repair a flexor tendon injury in his throwing arm.