He spent the 2016 season with the Single-A Bowling Green Hot Rods, posting a .283/.314/.438 slash line with 13 home runs, 81 RBI, and 17 stolen bases in 118 games for the team.

[3] In 2017, Sullivan split the year between the High-A Charlotte Stone Crabs and Double-A Montgomery Biscuits, hitting a cumulative .294/.324/.433 with 8 home runs, 74 RBI, and 18 stolen bases in 107 games.

[7] He spent the 2021 season with the Triple-A Durham Bulls, playing in 90 games and batting .223/.302/.375 with 9 home runs, 35 RBI, and 7 stolen bases.

[10] He spent the season with the Triple-A El Paso Chihuahuas, hitting .285/.339/.444 with 9 home runs and 81 RBI (tying a career-high) in 113 games.

On April 16, 2023, Sullivan was promoted to the major leagues for the first time after Luis Campusano suffered a left thumb sprain.