Thornton, 36, is a one-time All Star, having been named to the AL squad in 2010, a year in which he posted a 2.67 ERA and 1.01 WHIP while striking out 12 batters per nine innings. However, since that sterling year his numbers have gotten worse with each passing season.
That came to a head in 2013, when Thornton had his worst season statistically since 2007. Over 60 games split between the White Sox and Red Sox, he posted a 3.74 ERA and 1.43 WHIP, with a career-worst 6.2 K/9. Furthermore, the left-hander is looking more and more like a LOOGY going forward. Against right-handers in 2013, he allowed an 827 OPS versus lefties hitting for a 638 OPS.
The Yankees lost two of their top relievers from 2013 as Mariano Rivera retired and Boone Logan left for a big deal with the Rockies. Furthermore, until Tuesday the Yankees had been missing a left-handed veteran presence in their bullpen. Cesar Cabral pitched well over eight games in his first taste of the majors last year while David Huff struggled in more of a long-relief role.
Thornton's new contract will be split evenly by year, meaning he will earn $3.5 million in both 2014 and 2015.