Bullpen arms and anti-regression velocity

In a post yesterday, I pondered relief pitchers like Chad Qualls, Matt Albers and Jake McGee who have unexpectedly increased their fastball velocity with age. Their careers piqued my curiosity. And so I took a look at pitchers who have pitched in relief since 2010 and if their velocity has regressed or not. Let me share what I have discovered.

First, let me disclaim a few things. As always the disclaimer that I am not a math guy with a great handle on how to figure these things out. I am more like Joe Posnanski in knowing enough to be dangerous but not nearly as good at him at writing about my feeble discoveries and calculations.

Secondly, I am using Fangraphs.com's Pitch Type tool which lumps all fastball types together (4-seam, 2-seam, sinker). While that is inconvenient, it does make it easier than tracking three different pitch types.

And lastly, I am not talking about success rates, movement, the value of the fastball or anything but velocity. As most of us know, velocity has a lot to do with success (ahem, Mr. Sabathia) but not everything (ahem, Sabathia critics). Location and command are just as important.

The first thing I did was look at league averages. Each year since 2010, there has been a fairly consistent total of 135 to 137 qualifying relief pitchers and the averages have been constant. They are as follows:

Year, Ave Fastball for All, Ave Fastball for top 50

• 2010 - 92.45, 95.00
• 2011 - 92.50, 94.97
• 2012 - 92.51, 94.84
• 2013 - 92.65, 94.94
• 2014 - 92.47, 94.52 (SSS)

Two things pop up for me looking at those numbers. First, they are remarkably consistent from year to year, so it gives us a framework. And secondly, it is unbelievable that 37% of all relief pitchers throw some pretty serious cheese.

What I am now interested in is those relief pitchers that have pitched in all five of these seasons (or at least four of the five) and how many have had their velocity decrease (regress), increase (progress) and remain constant. And I am only interested in pitchers who have only relieved in that time period.

Going through all five years (that took hours!) I came up with 54 pitchers who pitched either all five or four of the five seasons. I may have missed a name or two, but the idea was to get a decent sample size. The raw numbers do not include factors like injuries, climate changes, etc. Nor does it take into account that in some cases, the fastball is not the relief pitcher's main weapon (think Luke Gregerson, Koji Uehara).

I considered a significant change anywhere over .5 MPH plus or minus. As you will see from my list below, fifteen saw significant increases in velocity over the time period. Twenty-three pitchers saw significant drops in velocity, which is what you would normally expect. That leaves us with 16 that haven't changed significantly either way, which is a story in and of itself.

The conclusions left still do not answer my question. How are guys like Jake McGee beating the time machine? McGee has added significant velocity in each season! How is Chad Qualls doing what he is doing? How about Matt Albers and his 6.3 K/9 rate suddenly blowing people out with fastballs?

Please don't think I am stirring up controversy. I am not making accusations in this day and age. Gosh, no. It's not that at all. It's just that to me, velocity is age relevant and somehow, fifteen pitchers are resisting arrest...arrested development that is and it sort of messes up my head.

Name	2010	2011	2012	2013	2014 (SSS)	1st to 2013	2014 age
Jake McGee	93.5	94.8	95.7	96.3	96.9	2.8	28
Chad Qualls	92.1	92.6	93.1	94	94	1.9	36
J.P. Howell	85.6	86.5	86	87.4	84.7	1.8	31
Junichi Tazawa		91.8	93.7	93.5	92.8	1.7	28
Craig Kimbrel	95.4	96.2	96.8	96.9	96.5	1.5	26
Logan Ondrusek	92.6	92.9	93.5	93.9	92.8	1.3	29
Jeremy Jeffress	95.4	96.8	94.7	96.7	95.4	1.3	27
Koji Uehara	88.1	88.8	88.9	89.2		1.1	39
Matt Albers	92.4	93.6	93.7	93.4	95.1	1	31
Tom Wilhelmsen		95.2	96.3	96.2	94.5	1	30
Jason Grilli		92.4	93.6	93.4	94.4	1	35
Fernando Rodney	95.6	95.5	96.1	96.5	93	0.9	34
Pedro Strop	94.9	94.3	96.9	95.8	95.5	0.9	29
Steve Delabar		94	94.6	94.7	92.6	0.7	30
John Axford	94.9	95.6	96.2	95.4	93.1	0.5	31
Francisco Rodriguez	91.1	90.3	91.8	91.4	90	0.3	32
Juan Gutierrez	94.7	94		95	94.7	0.3	31
James Russell	88.8	88.1	89.1	89.1	86	0.3	28
Mark Melancon	92.8	92.7	93.3	92.9	93	0.1	29
Joaquin Benoit	94	93.9	93.7	94.1	95.3	0.1	34
Dale Thayer	92.9	92.8	93.9	92.9	92.2	0	33
Joe Nathan		92.3	94	92.2	90.3	-0.1	39
David Robertson	91.9	93.1	92.2	91.7		-0.2	29
Jim Johnson	94	95.1	94.3	93.8	93.4	-0.2	31
Tyler Clippard	92.3	92.7	92.8	92.1	92.4	-0.2	29
Steve Cishek	92.5	92.7	92.2	92.3	90.1	-0.2	28
Jason Frasor	92.8	93.1	93	92.5	91.4	-0.3	34
Carlos Marmol	94.1	91.8	94	93.7	94.4	-0.4	32
Aaron Crow		95	94.5	94.6	91.8	-0.4	28
Ronald Belisario	94.9	93.5	94	94.4	94	-0.5	31
Casey Fien	91.5		92.8	91	92.3	-0.5	31
Drew Storen	94.4	95	94.6	93.9	92.2	-0.5	27
Matt Lindstrom	95.7	96	94.8	95	94.8	-0.7	34
Heath Bell	94	94	93.6	93.2	90.3	-0.8	37
Wilton Lopez	92.3	91.7	92.4	91.5	90.6	-0.8	30
Cesar Ramos	91.9	92.3	91.6	91.1	89.6	-0.8	30
Fernando Salas	91.3	91.2	91.8	90.4	93	-0.9	29
Sergio Romo	88.6	89.4	97.7	87.7	88.6	-0.9	31
Al Alburquerque		95.4	94.5	94.3	93.3	-1.1	28
Joakim Soria	91.9	91.4		90.8	89.5	-1.1	30
Aroldis Chapman	99.6	97.9	97.7	98.3		-1.3
Sergio Santos	95.9	95.3	94.8	94.6	93.7	-1.3	31
Kenley Jansen	93.9	93.3	91.9	92.4	94.9	-1.5	27
Bobby Parnell	96.5	97.2	95.7	95	92.3	-1.5	30
Antonio Bastardo	93.5	92.5	91.8	91.7	91.4	-1.8	29
Matt Thornton	96.1	95.8	95	94.2		-1.9	38
Chris Perez	94.6	93.4	94	92.7	93	-1.9	29
Rex Brothers		95.3	95.3	93.4	91.8	-1.9	27
Huston Street	91.3	90.1	89	89.4	88.6	-1.9	31
Addison Reed		94.9	94.6	92.8	93.4	-2.1	26
Luke Gregerson	90.6	89.7	89.2	88.2	87	-2.4	30
Jose Valverde	95.2	93.9	93.4	92.8	92	-2.4	36
Jonathan Papelbon	94.9	95	93.8	92	91.6	-2.9	33
Santiago Casilla	96.6	93.6	93.9	93.4	94.2	-3.2	34