BOSTON -- Acquired in July as left-handed relief insurance, Matt Thornton pitched 15 1/3 innings with a 3.52 ERA for the Red Sox this year, but the team declined his $6 million option for 2014 on Saturday. The buyout will cost them $1 million.
Thornton was traded from the White Sox in exchange for Brandon Jacobs, a 22-year-old outfielder who hit .237 with a .618 OPS at Double-A Birmingham after the trade.
At the time of the deal on July 12, the Red Sox had just one left-handed reliever, Craig Breslow. Thornton, the former White Sox closer, appeared needed. But the emergence of Drake Britton shortly after provided the team with another lefty to use. And by the time the playoffs rolled around, Felix Doubront was merely an extra in the starting rotation and instead added one more left-hander out of the 'pen. Thornton was never included on the playoff roster.
While Thornton's velocity was down slightly again, matching a decline in strikeouts for a fourth straight season, he was still effective against left-handed hitters, holding them to a .235 average.
Thornton joins a class of free-agent lefty relievers that includes J.P. Howell, Boone Logan and Javier Lopez.
Ian Browne is a reporter for MLB.com. Read his blog, Brownie Points, and follow him on Twitter @IanMBrowne. Jason Mastrodonato is a reporter for MLB.com. Follow him on Twitter @jmastrodonato. This story was not subject to the approval of Major League Baseball or its clubs.