2014 Bullpen Breakdown: Boston Red Sox

by Steven Grindstaff

What a revelation Koji Uehara was for the Boston Red Sox in 2013. The league leader in relief pitcher WAR, Uehara was absolutely brilliant.  Andrew Bailey just couldn’t stay healthy enough, leaving the door open for Uehara to put together a fantastic season.

Overall, the Red Sox had one of the top five bullpens in the majors during the 2013 season. Early in the offseason they were able to add the services of Edward Mujica, which will only strengthen what is already a strong bullpen. Look for this crop of pitchers to once again be one of the best in the majors, as the Red Sox defend their World Series title, though that’s not to say that they don’t carry their share of risk.



Koji Uehara
Uehara’s stat line looks incredible with strong strikeout rates, magnificent walk rates and a sparkling ERA. However, when looking more closely, there are some major red flags. First off, is a .188 BABIP sustainable? Well over the past three seasons he has been able to keep his BABIP around this vicinity, but take note he owns a .243 figure for his career.

Next, a LOB rate of nearly 92%. He owns a career mark that hovers around 80%, and over the past three seasons his LOB rate has been on the decline. How much longer can he keep this up? He was able to limit the home runs in 2013 with a HR/9 rate that is nearly half his career mark. Simply everything was clicking for Uehara in 2013, but if these numbers regress back to his career marks Uehara could be in for a rude awakening (or maybe getting out of the hitter friendly parks of Texas and Baltimore will lead to more success like 2013).  One more area to take note of is a miniscule 11.3% LD rate. He bettered his career mark by roughly 4%, but do you really believe this is sustainable?

There are some areas of major concern when digging deeper, but maybe the move to Fenway Park was something he needed to breakout. It’s going to be interesting to keep an eye on Uehara just to see if 2013 was a fluke or not.


Edward Mujica
Mujica saved 37 games for the Cardinals, but ended up losing his job late in the season to Trevor Rosenthal. Mujica really struggled late in 2013 and will look to rebound in a new uniform. He offers very limited strikeout upside, and his 0.70 walk rate was half his career total. Add this to a LOB rate in 2013 that was roughly 13% above his career mark, we can begin to see possible disaster on the horizon. If he can revert back to getting more groundballs and less flyballs, he may be able to limit the damage. A FIP of nearly a run higher than his ERA suggests that Mujica could be in for a rough 2014. It’s hard to buy into him going forward, but he should be able to rack up holds on a good Red Sox team.


Junichi Tazawa
Tazawa saw some regression in his numbers from 2012 to 2013, which was expected when you look back at the numbers and compare them to his career marks. As you can see, he continues the trend of excellent walk rates in the Red Sox bullpen. For the most part, his numbers are in line with what we can expect considering what he has done throughout his short career. He did get hit very hard, to the tune of a 27.2% LD rate. He also saw a huge spike in his FB rate and a significant decline in his GB rate between 2012 and 2013. Considering the small sample size of his numbers, it’s tough to gauge what type of pitcher he really is in regards to his batted ball profile. Nonetheless, Tazawa has some upside and should be next in line if something should happen to Uehara.

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