Marinez is the 18th pitcher on the White Sox roster, which now includes 35 active players.
After being acquired as part of the Ozzie Guillen trade with Miami, the 24-year-old posted a 4-2 record and 2.86 ERA in 40 relief appearances for Charlotte this season. Marinez's 65 strikeouts slotted him fifth among all International League relievers in strikeouts per nine innings.
He pitched 1 2/3 shutout innings in his only action for the White Sox on July 13 in Kansas City.
Manager Robin Ventura said the club simply wanted to add another arm to its arsenal.
"We're using a lot of guys," Ventura said. "They were talking about bringing Marinez up earlier in the year but once their season was over they decided to bring him up."