 Thornton made 40 appearances for the White Sox to start the 2013 season by going 0–3 and a 3.86 ERA.In 327 relief appearances with the White Sox spanning 299 innings, Thornton compiled with a 3.18 ERA, including a 2.55 mark in 2010.As of September 12 he led all eligible American League relievers with 12.3 strikeouts per nine innings.