When the Baltimore Orioles signed Koji Uehara to a two-year, $10 million deal in 2009, it was an impressive step into Japanese baseball for Baltimore, and it would lead to the signings of other prominent arms out of the Far East by the O’s in later seasons. Uehara had gone 102-54 from 1999 through 2006, posting a 3.01 ERA over 1,397.1 innings prior to moving to the bullpen in 2007 for the Yomiuri Giants, where he posted a 1.74 ERA over 55 appearances and 62 innings in 2007. He went back and forth between starting and relieving in 2008 before coming to America to pitch in the Baltimore system.
Uehara would make 12 starts in 2009, posting 4.05 ERA and 1.25 WHIP, solid numbers in a challenging home ball park and difficult AL East, but after the 2009 season, Uehara never started another game, and he likely won’t again due to his dominance out of the bullpen. In 86 outings out of the bullpen for the Orioles, Uehara posted a 2.27 ERA and 0.82 WHIP over 91 innings before being shipped to the Texas Rangers for Chris Davis and Tommy Hunter. The Orioles certainly deserve some praise in the Davis explosion in 2013, as he looked like a completely different player than he did in his time with the Rangers, but Uehara wasn’t chopped liver, posting a 2.50 ERA and 0.68 WHIP in 59 appearances over part of the 2011 season and all of the 2012 season in Arlington.
In 2013, however, things got weird for Uehara. His stuff or abilities have seemed to go to a new level. This explanation from MLB Network does a tremendous job of showcasing Uehara’s devastating repertoire:
Since arriving in Boston, Uehara has posted a 143:13 K:BB in 106 innings, with a 0.93 ERA and 0.59 WHIP. After the Red Sox paid for Andrew Bailey and Joel Hanrahan, only to see them both succumb to injuries in 2013, Uehara stepped into the closer position and has posted number just as dominant as Aroldis Chapman and Craig Kimbrel, while tossing a fastball with an average velocity of 89.2 mph in 2013 and 87.9 mph in 2014 (FanGraphs).
Opposing batters are hitting just .159/.189/.234 on the season and .164/.192/.293 against Uehara as a reliever in his career, and his K/BB in two seasons in Boston is an incredible 11.08, which is why it doesn’t show up on the graph (above). In a reliever-heavy era, where teams are carrying seven to eight relief pitchers on a 25-man roster, Uehara has maintained his dominance in his role while others have dealt with injuries or inconsistencies over the same time period. While Mariano Rivera dominated for so long with a cutter, Uehara has reinvented himself over the last several years with his splitter out of the bullpen. At 39, however, there isn’t much time left to see what Uehara can do at the major league level.
Despite the extensive use out of the bullpen, Uehara’s dominance is still, at times, overlooked. While the Red Sox struggle due to injuries and the lack of consistency from young players taking over major roles, Uehara continues to be the ferocious anchor of the bullpen, locking down wins with a pitch that falls off of the table like none other before it.