The White Sox claimed right-hander Zach Stewart off waivers from Pittsburgh, the team announced Thursday. Stewart pitched for the White Sox in 2011 and 2012 before heading to Boston as part of the deal that landed the Sox Kevin Youkilis last June.
Stewart, 26, pitched in 28 games with the White Sox, making nine starts. In his career, Stewart has a 7.51 ERA over 14 starts in which he's allowed 18 home runs. He's fared better as a reliever, but still owns a 5.02 ERA out of the bullpen with seven home runs allowed in 28 23 innings.
The right-hander was acquired by the White Sox in 2011 along with Jason Frasor in a deal with Toronto which sent Edwin Jackson and Mark Teahen to the Blue Jays. He came close to throwing a perfect game on Sept. 5, 2011 in Minnesota, holding the Twins without a baserunner until allowing a leadoff double to Danny Valencia to open the eighth inning. Stewart wound up throwing a one-hit shutout in that start.
The White Sox added Stewart to their 40-man roster, which now has 39 players on it.
Four of the team's top-10 prospects and a former All-Star are among the 19 nonroster invitees to White Sox big league camp this spring.
The team announced Monday that prospects Michael Kopech, Zack Collins, Zack Burdi and Spencer Adams have all been invited to camp next month. Everth Cabrera, an All-Star in 2013 for the San Diego Padres, Cody Asche, Cory Luebke and Geovany Soto are among the eight minor league free agents who also received an invitation. Pitchers and catchers report to camp in Glendale, Ariz. on Feb. 14 while the team holds its first full-squad workout on Feb. 18.
Kopech was acquired in the Chris Sale trade in December while Collins and Burdi were both selected in the 2016 amateur draft. Adams was drafted in 2014.
Signed earlier this month, Soto is expected to earn a spot on the 25-man roster. Soto, who played for the White Sox in 2015, finished last season with four home runs and an .809 OPS in 86 plate appearances for the Los Angeles Angels.
Cabrera, who produced 4.6 Wins Above Replacement between 2012-13, hasn't played in the majors since he appeared in 29 games for the Baltimore Orioles in 2015. Luebke, who has twice had reconstructive elbow surgery, finished with a 9.35 ERA in nine games for the Pittsburgh Pirates last season. Asche blasted 31 homers with a .240/.298/.385 slash line in 1,287 plate appearances since 2013 with the Philadelphia Phillies.
Other minor league free agents include: left-handed pitcher David Holmberg, right-handers Blake Smith and Anthony Swarzak, and catcher Roberto Pena.
White Sox minor leaguer pitchers Aaron Bummer, Brian Clark, Jace Fry and Matt Purke, infielders Nicky Delmonico and Danny Hayes, and outfielder Courtney Hawkins also have been invited to camp.