The Numbers Behind The Red Sox Bullpen's Implosion Since The All-Star Break

You know it's been ugly, but did you know it was THIS ugly?!

Aug 19, 2024; Houston, Texas, USA; Boston Red Sox relief pitcher Kenley Jansen (74) walks off the field as Houston Astros catcher Yainer Diaz (21) celebrates with teammates after hitting a walk-off home run during the ninth inning at Minute Maid Park. Mandatory Credit: Troy Taormina-USA TODAY Sports / Troy Taormina-USA TODAY Sports

Monday night's loss in Houston was the epitome of all that has gone wrong for the Boston Red Sox in the second half. It was simultaneously gut-wrenching and all too predictable.

After Masataka Yoshida's clutch pinch-hit home run made it 4-2 Boston in the top of the sixth inning, the Red Sox had a 76% win probability, per Baseball Savant. But the Houston Astros clawed back, scoring a run in the sixth and eighth innings before Yainer Diaz launched a walk-off home run off closer Kenley Jansen.

The loss was as consequential as it was painful. It dropped Boston to 4.5 games behind the Kansas City Royals for the third American League Wild Card spot, their largest deficit of the season, with just 38 games to go.

In just a month since the All-Star break, it's hard to count the number of games the Red Sox bullpen has blown on two hands. But the numbers behind the bullpen's implosion are as fascinating as they are terrible, so let's do a quick deep dive:

Boston had leads in the eighth inning or later twice against the Los Angeles Dodgers, once against the Colorado Rockies, once against the New York Yankees, once in the first Astros series, once against the Texas Rangers, and, of course, last night.

Seven back-breaking losses, each of which could be the difference between a playoff spot and sitting on the couch in October.

In the 29 games since the All-Star break, the Boston bullpen has a 6.93 ERA. That's more than a run worse than the second-worst team, the Chicago White Sox, and more than two runs worse than the third-worst team, the struggling Rangers.

And it's not just that the Red Sox have been blowing games, but their trade deadline was focused on improving the bullpen specifically. Lucas Sims and Luis Garcia, their two main acquisitions, have both contributed immensely to the blowup, with three blown saves and a combined 9.82 ERA.

On the whole, the Red Sox have blown an astonishing 13 of the 17 save opportunities they have had since the break. No other team has blown more than eight, and the Dodgers are 12 for 20 in that time frame.

If you're more of an advanced stats person, consider this: the Red Sox bullpen has been worth -2.1 fWAR since the All-Star Game, per Fangraphs. The second-worst team, the White Sox again, has been worth -0.7.

They have stranded the fewest baserunners since the Midsummer Classic, at 60.5%. And their win probability added in that time frame is a whopping -3.85, meaning they have essentially cost the Red Sox four wins compared to the expected outcomes of the situations they have inherited.

These numbers aren't just bad. They're starting to become historic. And if the Red Sox bullpen can't figure out a way to drastically improve as a unit, their playoff push is already doomed.

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