The Orioles’ Soft-tossing Bullpen

The Orioles have, for the second time in three seasons, the best bullpen in baseball. Granted, this is somewhat subjective, but if we go by WPA, or the total Win Probability Added by O’s relievers, then they’ve been the best in the game. Back in 2012 the bullpen posted a 13.86 WPA, by far the best mark in the game. The Rangers finished second with a paltry (yet excellent) 8.00 WPA, to truly put the O’s performance in perspective.

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So far this season they’ve posted 7.08 WPA, besting the Padres and the rest of MLB. The O’s bullpen of 2014 isn’t going to post the historic numbers that it did a few seasons ago, but it will still easily finish top 5 in MLB by the end of the season.

Interestingly, the O’s bullpen has done it with less of what we associate with dominant relievers than other clubs. That thing we associate with dominant relievers is velocity of course, something the O’s sorely lack. Now I haven’t done the research to see how correlated velocity is with bullpen performance. Obviously the O’s serve as a great counter argument to the idea that velocity is a requirement for having a good bullpen. However, conventional wisdom would tell you that velocity is crucial.

The Data

To wit, 17 of the top 20 relievers for fastball velocity, with at least 10 innings pitched as relievers have posted positive WPA figures. Those 20 pitchers have combined to produce 20.54 WPA, with an average fastball ranging from 95.9 mph (Vic Black) to 100.3 mph (Aroldis Chapman). For context, the next 20 pitchers in terms of velocity have combined to post 13.33 WPA, and the next 20 just 2.3 WPA.

 Let’s take a look at it statistically, to get a sense for where the O’s pitchers fall. For this exercise we’ll look at only fourseam fastball velocity, just as above. The mean fourseam velocity for a reliever in 2014 with at least 10 innings pitched is 92.14 mph. The standard deviation for this population is 2.57 mph. That means that a pitcher who throws a 94.7 mph fastball is approximately one standard deviation above the mean.

This guy leads the best bullpen in MLB (June 6, 2014 - Source: Greg Fiume/Getty Images North America)

This guy leads the best bullpen in MLB
(June 6, 2014 – Source: Greg Fiume/Getty Images North America)

So where do the O’s pitchers fall in relation to the mean fastball velocity? Well, there’s not a single O’s pitcher two or more standard deviations from the mean. That list though is small, only including Aroldis Chapman (100.3 mph, 3+ standard deviations) and Carter Capps (97.7 mph, 2-3 standard deviations). There are then 36 pitchers between one and two standard deviations above the mean, only one of which is an Oriole: Tommy Hunter. For context, these pitchers’ fastballs range from 94.8 – 97.1 mph. The pitchers in this group average about 0.85 WPA this season, meaning that the O’s lone representative in this group isn’t even carrying his own weight with his 0.5 WPA this season.

The next group is less than one standard deviation above the mean. The pitchers in this group range from 92.3 mph to 94.7 mph, and the sample includes 106 pitchers. These 106 relievers have combined to produce just 7.44 WPA, so expectations for these middling guys should be low. This group includes three O’s pitchers: Zach Britton (94.2 mph), Andrew Miller (93.8 mph), and Brad Brach (93.4 mph). Those three are also among the best in this group when it comes to WPA. In fact, among these 106 pitchers they rank 1st, 12th, and 13th respectively in WPA this season. These guys have done much of the heavy lifting for the bullpen*. It’s worth noting that Ryan Webb would fall in this group as well, though he does not throw a fourseam fastball, and as such was removed from this survey. The 93.0 mph two-seamer that he throws has helped him post a 1.18 WPA so far in 2014.

*Note – Andrew Miller accumulated nearly all of his WPA with Boston this season.

There are an additional 90 relievers who are one standard deviation below the mean in terms of velocity, and this list also includes three O’s pitchers. This population as a whole has posted 12.05 WPA, faring slightly better than their harder throwing brethren. The pitchers in this sample range from 89.7 mph to 92.3 mph. That includes TJ McFarland (89.7 mph), Brian Matusz (90.5 mph), and Josh Stinson (92.0 mph). Those three have been poor at best this season, combining to produce -0.19 WPA. The best pitcher in this sample has been former flamethrower Jonathon Papalbon who has posted 2.84 WPA with his 91.4 mph fastball.

Now we get into the really slow guys. This next group is between one and two standard deviations from the mean, meaning they throw somewhere between 87.3 mph and 89.6 mph. The 39 pitchers in this sample posted 12.02 WPA,which comes out to slightly more than a third of a WPA per pitcher. This group includes two Orioles: Darren O’Day (87.5 mph) and Evan Meek (89.2 mph). O’Day has been one of the best relievers in baseball, and his 2.70 WPA is second to only Koji Uehara (3.5 WPA, 88.0 mph) in this sample. Meek on the other hand has been awful posting a -0.76 WPA, the third worst figure in this sample.

The remaining seven pitchers are two or more standard deviations from the mean, which means they threw less than 87.2 mph. The group is rounded out by Randy Choate who has thrown his fastball an average of 83.4 mph while posting a 0.36 WPA in the process. There were no Oriole pitchers in this sample.


The weak throwers actually produce pretty decent numbers when you think about it. The seven pitchers that throw 87.2 mph or less have combined to post 2.78 WPA so far in 2014. Now, there’s some survivorship bias in this, because soft tossers won’t last long in the league unless they prove to be effective quickly. That said, it’s interesting that the O’s have been able to pitch so well despite having precious few flamethrowers.

The table below includes expanded numbers for all pitchers in the O’s bullpen this season, with their velocities and WPA clearly visible. This list of 14 pitchers includes anyone who has thrown a relief pitch for the O’s this season:


Essentially what you have is five guys who all throw harder than the average reliever and have provided most of the value to the club. In fact the 5.99 WPA provided by Hunter, Britton, Miller, Brach, and Webb accounts for 84.4% of the WPA provided by the O’s bullpen to date.

After that top five you have eight guys that generally don’t throw very hard, and also provide no real value to the club. That’s not totally fair, as McFarland and Guilmet have posted positive WPA, but generally these guys trend out negative. Those eight pitchers have combined to post -1.60 WPA this season. For anyone claiming that Buck gets the most talent out of these guys, well… you’re wrong. Basically all of these guys could come or go in the ‘pen and the O’s wouldn’t be worse for it. In fact, Buck should probably go out of his way to avoid throwing any of these pitchers very much at all. There’s no “hot hand”.

Then there’s Darren O’Day. He throws real slow on account of his being a side-arm pitcher, but the 53.2 IP he’s thrown this season have nearly all been excellent. He is, by all accounts, the sixth guy that Buck should use out of the bullpen. Not to say that he’s the sixth best pitcher, but rather that he along with Britton, Hunter, Miller, Brach, and Webb should essentially be Buck’s go-to bullpen options. TJ McFarland would make a nice 7th reliever / long man / swing man.

The O’s bullpen may rank 28th in MLB in fourseam velocity from their relievers (91.7 mph on average), but that’s actually kind of misleading. The slowest fastball among the guys we’d call “useful options not named O’Day” is 93.0 mph. O’Day’s 87.5 mph fastball may pull down the team’s velocity a bit, but a seven-man bullpen of the guys I listed above would still be the best in baseball. They’d also rank a lot closer to the middle of the pack in terms of velocity.

While the Orioles don’t have any guys that throw 98 mph on a regular basis like some teams (the Cardinals 94.6 mph average velocity leads MLB), they do have a group of above average velocity guys that are extremely effective. They also have Darren O’Day who might be the most interesting reliever in baseball. It seems like every team has a guy that goes out and hits triple digits in late innings these days.

The Orioles don’t really have that (Hunter gets close), but they do have six of the best relievers in baseball when it’s all said and done (O’Day 8th in MLB in WPA, Britton 9th, Brach 33rd, Miller 35th, Webb 46th, and Hunter 92nd). For those of you keeping score at home, that bullpen out there has six of the top 92 relievers in baseball, and five of the top 46. That’s pretty damn impressive, regardless of how hard they throw.

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About the author

Jeff Long   

Orioles Analyst

Jeff was the owner of the Orioles blog Warehouse Worthy, which focused on making advanced statistics a part of the conversation for the average fan. Outside of baseball, Jeff is a graduate of Loyola University where he received his Bachelor’s and Master’s in Business Administration. The Maryland native currently works for an Advertising Agency in downtown Baltimore. Previously a contributor to Beyond the Boxscore, he joined Baseball Prospectus in September 2014. Now a Sr. Orioles Analyst for BSL, you can reach him at

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One Response to The Orioles’ Soft-tossing Bullpen

  1. Luke says:

    One thing I’ll say about Britton. He my not throw 100 mph, but that 97 mph sinker is just unfair.

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