The 35-year-old pitched with the Los Angeles Dodgers in 2013. He went 4-7 with a 4.26 ERA in 105 2/3 innings (24 games, 22 starts). He posted a 84 ERA+ and a -0.6 WAR this past season. Capuano has had good seasons over his career, as he has posted an ERA+ over 100 three times (minimum 100 innings). Capuano has never pitched in the American League, however he is 9-8 with a 4.78 ERA in 131 2/3 inning pitched against AL teams. Over his career, Capuano has a 4.27 ERA, a 2.68 K/BB ratio, and a 97 ERA+.
The Red Sox have been looking for pitching help this off-season after finishing 14th in the Major Leagues in pitchers' ERA. Also, following the loss of Ryan Dempster this season, they have needed another reliable starter to fill the void. And, Chris Capuano should do that. He's a veteran, and can toss plenty of solid innings.