Thornton, 37, is coming off a year where he recorded a 3.74 and a 30/15 K/BB ratio over 47 1/3 innings pitched between the Chicago White Sox and the Boston Red Sox. Left-handed batters hit just .235 (19-for-81) against Thornton last year, though he did allow three home runs.
An All-Star in 2010, Thornton has had several solid seasons as a member of the White Sox. He has 23 career saves, and had three straight seasons from 2008-10 where he recorded a sub-3.00 ERA.
Thornton should fill the shoes of Boone Logan, who left for the Colorado Rockies after signing a three year, $16.5 million contract. He joins David Robertson and Shawn Kelley as the only relief pitchers certain to be on the team’s Opening Day roster.