To make room for Thornton on the 25-man roster, right-hander Steven Wright was sent to Triple-A Pawtucket. Left-hander Andrew Miller, who suffered a left-foot sprain, was placed on the 60-day disabled list to open a spot on the 40-man roster.
Thornton, 36, was acquired by the Red Sox along with cash considerations from White Sox two days ago in exchange for minor league outfielder Brandon Jacobs.
In 40 appearances for Chicago this year, he went 0-3 with a 3.86 earned-run average, 10 walks, and 21 strikeouts.
The Red Sox were shut out 3-0 last night by the Oakland Athletics. Boston (58-38) leads the American League East, 3 ½ games ahead of the Tampa Bay Rays (54-41).
Wright, 28, earned the first win of his major league career two days ago in a 10-inning game against the Seattle Mariners, throwing 5 2/3 scoreless innings of relief.
In his two appearances for Boston in 2013, he is 1-0 with a 4.82 ERA, six walks, and seven strikeouts. He rejoins Pawtucket where he was 4-5 with a 3.81 ERA, 49 walks, and 70 strikeouts in 16 starts. At the time of his promotion to the majors on July 10, he had thrown 17 2/3 consecutive scoreless innings over his previous three outings.
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