The bullpen overachieving is all about what you expected them to achieve. Did you expect them to replicate last year? Did you expect them to drop off? Many Kool Aid drinkers on this site said the sox "would be fine" with their pen. One by one, Walden, Barnes, Brasier and Workman are having good individual seasons. The problem comes about when they are used to procure close leads and it's become worse come June. The makeup of a pen is not about the individual parts. You could have one long reliever who is just getting bombed but you need a live body to absorb garbage time. They will skew the stats. The makeup of a pen is how they can take a close lead and finish the game. That is really when you need them. Going by the sox website...
Saves and Save opps
March 1 for 1
April 7 for 10
May 4 for 10
June 5 for 12
Now the stupid blown save stat counts anything I think beyond the 6th inning, but it could include any lead handed over. Not entirely sure. But it doesn't just incorporate the 9th inning. As it stands, per MLB.com, the sox are 17 for 33 in saves, leading to a 51.5% conversion rate. The big league average is 65.5%. Only the Mess at 48% are lower. The sox are 29th in save percentage. The sox have had the 8th most save opportunities in baseball, so considering that they have the second worst conversion rate yet have the 8th best amount of chances, this is why the pen is failing. I get the pen WAR and ERA is good. Heck, the sox pen ERA is a few points lower than the Yankees vaunted pen. But the Yanks convert 70% of their save chances in total and when we get to the 9th, we have a closer with a 92% conversion rate.