The 24-year-old Stewart was 1-2 with 5.96 ERA in five starts with the Sox this season, after going 2-0 with a 2.05 ERA in 22 innings in spring training.
Wright, 25, was thrown on the 15-day disabled list in spring training with elbow inflammation. Wright returned to action in early April with the triple-A Charlotte Knights, where he made four starts, compiling 3.38 ERA in 18 2/3 innings.
Last season with the Sox, Wright went 14-12 with a 5.18 ERA. Wright led the team in strikeouts with 136 and was second in innings with 196 1/3. The Sox haven't announced when Wright will make his first start. With Monday's day off, the Sox were scheduled to go to a four-man rotation with Colon moving ahead one day. That would leave Wright set for Saturday against the Mariners, who he is 2-0 (four starts) against with a 3.67 ERA (27 innings).