Fastball Speed Bounce Back Candidates

Here at Fangraphs, we have been writing quite a few articles on the fastball speeds (here and here and here and here). The main reason for the articles is that fastball speeds stabilize fairly quickly. They can be used to understand how a pitcher may perform in the future because fastball speed is directly related to both strikeout rates and runs allowed. With this knowledge, I am going to look at how a few pitchers, that saw their velocity drop in 2011, are doing in 2012.

Just because a pitcher loses velocity doesn’t mean that can’t bounce back. An example of a bounce back was Justin Verlander in 2008. Here is his fastball velocity (MPH), ERA and K% from 2007 to 2009

2007: 94.8 MPH, 3.66, 21.1%
2008: 93.6 MPH, 4.84, 18.5 %
2009: 95.6 MPH, 3.45, 27.4%

Pitchers can bounce back, so I wanted to see if any pitchers were able to bounce back. Before the 2012 season started, I asked my fellow Fangraph writers if they could give me a list of players that had a large drop in velocity from 2010 to 2011 (if any readers know of any more pitchers, please let me know and I will add them to the list). The pitches were Brett Myers, Bronson Arroyo, Jon Rauch, Jair Jurrjens, Francisco Cordero, Francisco Liriano, Chris Tillman and Matt Capps. All except Capps and Tillman have thrown so far this season. Here is each pitcher and their 2010 to 2012 FB speeds, when available, and their 2010 and 2011 K%:

Name	2010 FB Speed	2010 K%	2011 FB Speed	2011 K%	2012 FB Speed
Brett Myers	89.3	19.2%	88.1	17.5%	89.0
Bronson Arroyo	87.8	13.8%	86.7	12.6%	85.9
Jon Rauch	90.8	18.8%	89.4	16.0%	88.6
Jair Jurrjens	91.1	17.2%	89.1	14.4%	87.5
Francisco Cordero	94.5	18.7%	93.0	15.3%	92.1
Francisco Liriano	94.2	24.9%	91.8	19.0%	90.2
Chris Tillman	90.5	13.1%	89.5	16.0%	–
Matt Capps	94.1	19.3%	93.0	12.4%	–

From 2010 to 2011, this group of pitchers saw their FB velocity drop by an average of 1.5 MPH. Over the same 2 years, their K% dropped by 2.7% on average or a 1.9% drop in K% for each drop in 1 MPH.

So far in 2012, only one from the group has seen their fastballs have jumped back up in velocity, Brett Myers. Myers was likely to see some level of fastball speed increase since he was going from being a starter to being a closer. On average, the group has seem their fastball velocity drop another 0.8 MPH in 2012 from 2011.

This continued drop in velocity is interesting and raises a few questions. Does a pitcher stay at one speed and once they start to drop in speed, they just continue a long slide downward (see Tim Lincecum)? Is the continued drop only for pitchers that see large drops instead of smaller drops in velocity? It seems that I have a little more work ahead of me this week.

Fastball velocity can tell quite a bit about a pitcher with just a small sample of data. For pitchers that saw a drop in velocity from 2010 to 2011, there has not been much good news in 2012. There is possibly some more work to be done to see if pitchers can actually recover from such a large drop in velocity.