Stiever was recalled from the alternate training site to serve as the 27th man for Sunday's doubleheader in Boston.
The 23-year-old missed out on the Opening Day roster but will join the big-league club Sunday for the first time this season. The White Sox have yet to announce their official starter for Game 2, but Stiever is a strong bet to take the mound with Dallas Keuchel starting the matinee. The young right-hander made his major-league debut last year and surrendered seven runs with a 3:4 K:BB over 6.1 innings.