Stiever, the No. 6 prospect in the organization according to MLB.com, is the scheduled starter for the series finale against the Detroit Tigers at Guaranteed Rate Field.
Stiever went a combined 10-10 with a 3.48 ERA, 27 walks and 154 strikeouts in 26 starts in 2019 with Class-A Kannapolis and Winston-Salem.
The Sox also announced two more roster moves, optioning pitcher Alex McRae to Schaumburg and transferring pitcher Carlos Rodon (left shoulder soreness) to the 45-day injured list.
McRae appeared in two games after being called up from Schaumburg on Sept. 5. He allowed one hit in three scoreless innings.