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Battle of the Bullpens (Red Sox vs Astros)

Will Kimbrel bow to the Astros?
Chase Madorsky of

So today, we have the start of the battle between the two best teams in the AL. These teams on paper stack up extremely well, for what should be an exciting few game series. I don’t think many would argue that on paper, the Astros have the advantage in Starting Pitchers and the Red Sox teams have the advantage in offense. With both teams stacked with potential Cy Young winners, MVP candidates, and all-stars, what more could you ask for?

Well by the stats the Red Sox and Astros both have a bullpen ranking in the top 5 in the MLB. Let’s take a deeper look into the stats and who the members of each team are.

Relief Pitcher Stats

Red Sox – 3.48 ERA, 3.68 FIP, 3.86 xFIP in 485 IP, with 9.73 K/9 and 3.69 BB/9

Astros – 2.93 ERA, 2.99 FIP, 3.26xFIP in 415 IP, with 10.79 K/9 and 2.38 BB/9

The Astros throughout this season, have ranked #1 or #2 in almost all important statistics related to the bullpen. Even before they added Osuna and Pressly. And across the board, they seem to be ahead of the Red Sox on a team basis


Craig Kimbrel – 4-1, 2.45 ERA in 55 IP, 3.28 FIP, 3.07 xFIP, 13.74 K/9, 4.42 BB/9

This is going to sound insane, but this is a down year for Kimbrel. His ERA is 0.58 higher than his career average, his K/9 is almost down by a full point, and his BB/9 is up a full point. He’s had some excellent luck keeping his stats from showing a true reflection of performance. With his xFIP more than double last years, and more than a point higher than his career average.

Roberto Osuna – 2-2, 2.45 ERA in 29.1 IP, 1.96 FIP, 3.48 xFIP, 8.59 K/9, 0.92 BB/9

This year has obviously been a strange year for Osuna due to the well documented issues outside of the game. With that said, Osuna has been rising the charts of elite closers. It is crazy to think that he is just 23 years old. With all of that said, Osuna’s statistics are down a little year over year. Since being traded to the Astros though, he has returned closer to his career averages (1.93 ERA, 1.87 FIP, 9.6 K/9 and 1.3 BB/9)

Personally, I would call this a toss-up. Both are elite relievers, with Kimbrel definitely having a stronger career to date. The down year from Kimbrel and Osuna’s off-field struggles make this more interesting. It is cool to see that they have identical ERA’s with the advanced statistics seeing Osuna as more sustainable. Even with Osuna’s success with the Astros, I am giving the slight edge to the Red Sox, as Kimbrel is just plain intimidating.


The Red Sox had 6 other relievers pitch at least 30 IP:

Joe Kelly – 60 IP – 3.75 ERA, 3.57 FIP, 4.00 xFIP, 9.0 K/9, 4.20 BB/9

Matt Barnes – 58.1 IP – 3.39 ERA, 2.71 FIP, 2.81 xFIP, 14.19 K/9, 4.47 BB/9

Heath Hembree – 55 IP – 3.93 ERA, 3.84 FIP, 3.55 xFIP, 11.78 K/9, 4.25 BB/9

Hector Velazquez – 49.1 IP – 2.92 ERA, 3.58 FIP, 4.46 xFIP, 5.11 K/9, 2.33 BB/9

Brandon Workman – 34.2 IP – 2.60 ERA, 4.56 FIP, 4.13 xFIP, 8.05 K/9 2.86 BB/9

Brian Johnson – 31 IP – 4.94 ERA, 3.41 FIP, 4.02 xFIP, 8.42 K/9, 2.61 BB/9


Collin McHugh – 64 IP – 2.83 ERA, 2.73 FIP, 3.12 xFIP, 11.81 K/9, 2.25 BB/9

Brad Peacock – 58.2 IP – 3.07 ERA, 3.49 FIP, 2.92 xFIP, 13.50 K/9, 2.91 BB/9

Hector Rondon -51.2 IP – 2.09 ERA, 2.71 FIP, 3.46 xFIP, 10.10 K/9, 3.14 BB/9

Will Harris – 51 IP – 3.88 ERA, 2.45 FIP, 2.69 xFIP, 10.59 K/9, 2.29 BB/9

Joe Smith – 40.2 IP – 3.10 ERA, 3.45 FIP, 3.44 xFIP, 9.52 K/9, 1.99 BB/9

Chris Devenski – 40.2 IP – 4.20 ERA, 4.23 FIP, 3.87 xFIP, 10.18 K/9, 2.66 BB/9

Tony Sipp – 40.3 IP – 2.18 ERA, 2.52 FIP, 3.78 xFIP, 9.55 K/9, 3.00 BB/99

High level glance at all relief pitchers over 10 IP


Red Sox (9/14) under 9.0

Astros (0/10) under 9.0


Red Sox (8/14) over 3.0

Astros (1/10) over 3.0

I think that a simple glance here shows a key advantage for the Astros. They simply have an unmatched depth of their bullpen. The fact that Tony Sipp is the only reliever with over a 3.0 BB/9 and that they do not have one reliever with less than 9.0 K/9 is simply astonishing.


Both the Red Sox and Yankees are known for the dominant bullpens that strike fear in the league. The Astros on the other hand, have the most underrated bullpen in baseball. I have to say that looking at both individual performances and the depth on each team, that I would say the Astros have the advantage here.

One thing that is not covered above, is the mid-season acquisition of Ryan Pressly. I remember when we were looking at trade targets I mentioned him as a potential fit the day before the trade, and he’s far exceeded everyone’s expectations. I had been playing around with an article for Pressly over the past week, but MLB actually just released an excellent piece with a very similar theme to what I was writing.

Here are a few key takeaways from the article: Pressly has the second highest spin rate on his curve ball in all of baseball, his velocity increased from averaging 93 to 96, he has 22 K’s to 0 BB since joining the Astros with a 1.15 ERA.

What do you guys think? Who has the better bullpen? Comment and tell me your thoughts!


Who has the better bullpen?

This poll is closed

  • 97%
    (161 votes)
  • 2%
    Red Sox
    (4 votes)
165 votes total Vote Now