Kenley Geronimo Jansen (born September 30, 1987 in Curaçao, Netherlands Antilles) is a pitcher in Major League Baseball with the Los Angeles Dodgers organization. On May 4th, 2011 he was optioned to the Dodgers' Double-A affiliate, the Chattanooga Lookouts.
Jansen was signed as an undrafted free agent catcher by the Dodgers in 2005 and was assigned to the Rookie Class Gulf Coast Dodgers, where he played in 2005 and 2006. He split 2007 between the Ogden Raptors and the Class-A Great Lakes Loons. In 2008 with the Loons, he hit .227 and 9 home runs in 79 games.
In 2009, he was the starting catcher for the Netherlands team in the World Baseball Classic. In the Netherlands upset of the favored Dominican Republic team, Jansen threw out Willy Taveras on an attempted steal of third base in the ninth inning, a key play in the game.
With the Inland Empire 66ers of San Bernardino in 2009, the Dodgers began an attempt to convert Jansen from a catcher into a relief pitcher. After the season, he pitched in the Arizona Fall League and was added to the Dodgers 40 man roster. On May 15, 2010 he was promoted to the Double-A Chattanooga Lookouts, where he was selected to the mid-season Southern League all-star game.
On July 23, 2010, Jansen was promoted to the Dodgers. He made his Major League debut in relief on July 24 against the New York Mets, pitching a scoreless inning, retiring all three batters he faced, striking out two. The very next day on July 25, he recorded his first Major League save, when he pitched a 1-2-3 inning against the New York Mets.
On August 26, 2010, Jansen walked and scored a run in his first Major League plate appearance at Miller Park in Milwaukee against Yovani Gallardo. He collected his first Major League hit on August 31, 2010 at Dodger Stadium. The hit was a single up the middle against Kyle Kendrick of the Philadelphia Phillies. He recorded his first Major League win against the Houston Astros on September 11, 2010 in Minute Maid Park.
He appeared in 25 games with the Dodgers in 2010, working 27 innings with a 1-0 record and a 0.67 ERA. He also saved four games in 2010.
In 2011 Jansen became a key member of the Dodgers bullpen. He was 2-1 with a 2.85 ERA in 53.2 innings and saved 5 games. He also struck out 96 batters, setting a new Major League season record with 16.10 strikeouts per nine innings.