A four-time All-Star and 2011 Rookie of the Year, Kimbrel has become one of baseball's best closers, with a 1.63 ERA and a 1.72 FIP in six years in the majors. Just last year with San Diego, he had a 2.58 ERA and a 2.68 FIP, striking out 13.2 batters per nine innings and walking 3.3. Last year's Sox closer, Koji Uehara, will likely be bumped to the eighth inning with Kimbrel's arrival.
Kimbrel, 27, is due $11,250,000 next year, $13,250,000 in 2017 and has a $13 million team option in 2018.
In return, the Padres acquired four prospects: outfielder Manuel Margot, infielders Javier Guerra and Carlos Asuaje, and left-handed pitcher Logan Allen. Margot, 21, was ranked as the third-best prospect in the Boston system by MLB.com and is highly regarded as a five-tool player. Shortstop Guerra, 20, was ranked sixth in the Red Sox system; Asuaje, 24, was ranked, 23rd; and Allen, 18, was ranked 25th.