Sullivan was acquired in a trade with the Gary SouthShore RailCats on July 26, where he hit .275 in 10 games. A Stockton, Calif., native, Sullivan spent the previous three seasons in the White Sox organization, reaching as high as High-A Winston-Salem. The lefty began his professional career with the White Sox Arizona League affiliate, posting a .287 average. He was promoted the following year to Kannapolis, where he racked up 21 doubles and 31 stolen bases for the Intimidators, in addition to his only two professional home runs. After starting the 2017 season with Kannapolis, Sullivan was promoted to Winston-Salem, where he played two games before being released in early July. Sullivan played collegiately at Pacific University, where he was a career .304 hitter over four seasons and played with his younger brother, Brett, for his last three years with the Tigers. He was selected by Chicago in the 14th round of the 2015 MLB Draft.