Wright gave up six hits and one walk in the game, lowering his ERA to 4.22. Wright took a loss in his first start, giving up four runs in 4 1/3 innings.
The Sox were up 1-0 heading into the seventh, scoring on a Thomas home run -- his team-leading eighth of the season -- in the first inning.
That was all the Sox were able to do against Orioles' starter Rick Helling through the first six innings, but put up a big four-run spot in the seventh.
Willie Harris pinch ran for Paul Konerko, who was hit by a pitch, and reached second on an Armando Rios sacrifice bunt. After Joe Crede popped out for the second out, Sandy Alomar singled up the middle for the second time of the game, scoring Harris and giving the Sox the 2-1 lead.
Helling was pulled after D'Angelo Jimenez hit a double off the wall in right, advancing Alomar to third. With B.J. Ryan pitching, Jose Valentin singled in both runners to put the Sox up 4-1, and Thomas then doubled off Rick Bauer, scoring Valentin.
Carlos Lee batted fifth and went 2-4, while Jimenez and Valentin each went 1-4 at the top. Konerko went 1-2 and Harris went 1-1 with a stolen base. The Sox turned two double-plays in the game.
The Sox will be going for their 20th win on Thursday in the series finale, with Bartolo Colon going up against Sidney Ponson. The game will start at 7:05 p.m. CT and will be televised on Fox Sports Net Chicago.