Found: Verlander’s Velocity
I love the BIS pitch data statistics that are available here on FanGraphs. One of the first things we noticed using that data this season was that Justin Verlander’s fastball disappeared in April. He was throwing 91-92 instead of his usual 94-95, and his performance suffered as a result. He walked 18 and struck out just 20 batters in his six April starts, leading to a 6.50 ERA. His struggles were a major reason why Detroit failed to live up to expectations early on.
As the calender rolled into May, however, Verlander’s velocity started to pick up. After averaging just a 91.9 MPH fastball during his first three starts of the season, his fastball averaged 93.6 MPH during May, and his performance improved right along with the velocity spike. In 39 innings in May, he walked 13 and struck out 24 while posting a 3.92 ERA. It still wasn’t classic Verlander, but it was at least encouraging.
Enter June, and it’s safe to say that Verlander is back. His average fastball is now 94.5 MPH, sixth best in baseball during this month, and the results are what we expected from a guy who looked like an emerging ace last season. He’s walked 10 and struck out 28 batters in 27 1/3 innings, dominating hitters and holding them to a .575 OPS.
Whether it was just a tired arm phase or a mechanical tweak, Verlander’s fastball is back, and he’s pitching like the Tigers thought he would heading into the year. Detroit fans have to be happy to have their ace back to pitching like one, and it’s even more comforting that there’s a verifiable explanation for the improvement. For all the talk of guys learning how to pitch without their best stuff, Justin Verlander is clearly a better pitcher when he’s throwing 95 instead of 92.
Kent Bonham said,
June 26, 2008 @ 8:50 am
Not specific to this post, Dave, but just something I’ve always wondered: What confidence levels are associated with the velocity readings? Actually, “confidence level” probably has a very specific statistical meaning that I’m probably bastardizing, but…
If BIS logs a fastball at 91.6 MPH, what are the chances the pitch was 91.2 MPH or 92.0 MPH (or whatever)?
Mike Fast said,
June 26, 2008 @ 11:30 am
Kent,
PITCHf/x gets pitch speeds within about 1 mph of random measurement error for each individual pitch. There may also be systematic errors of a similar magnitude.
Radar gun measurements are what BIS uses, unless I am mistaken. These are subject to much greater error and are much more operator and condition dependent than PITCHf/x. So for a specific pitch here or there, it wouldn’t surprise me if BIS data is 5 mph off. But once you aggregate over hundreds of pitches the error should go down well below 1 mph, I would guess.
Dave Cameron said,
June 26, 2008 @ 12:04 pm
Like Mike said, radar velocities on any given pitch can be hilariously wrong (go to any minor league game, sit behind the scouts, and wait a few pitches - you’ll inevitably see a “108″ pop up), but for the data displayed on fangraphs, I’m sure those obvious errors aren’t counted in the averages. I’d imagine that the error bars around the data displayed here is probably less than 0.5 MPH - over hundreds of pitches, you’ll get a pretty accurate reading of what a guy throws.
Scotsw said,
June 27, 2008 @ 8:14 am
108???
And these are devices the police rely on? That doesn’t do much for my “confidence level.”
Mike Fast said,
June 27, 2008 @ 8:45 am
One of the problems with using a radar gun to determine pitch speed is that there are a lot of things moving at different speeds–the pitcher’s arm, the pitcher’s hand, a decelerating baseball–all of which generate radar returns, and you have to reliably pick out which one of those speeds you want to measure. The pitcher’s hand after release is the fastest-moving object, and that may be the source of the 108-mph readings.
There may be some radar experts who can explain it better than I can, but that’s what I understand as the difficulty involved.
Scappy said,
June 27, 2008 @ 3:36 pm
I am still surprised that they have not tried putting some type of accelerometer and radio transmitter inside of a baseball yet. The radio transmitter could be used to track position and time of the baseball throughout the game and the accelerometer would help give batted ball information because you would be able to know when the ball hits the ground.
This is major league baseball, they make millions upon millions of dollars, who cares if each ball costs 20 bucks.
Mike Fast said,
June 27, 2008 @ 7:07 pm
Video tracking of the ball is not that hard. It’s probably cheaper (and more accurate?) than a radio transmitter system, and you don’t have to mess with the baseball.
It really is an issue of cost and return, though. Ultimately I believe the video tracking system for the whole field (i.e., HITf/x) is going to happen within the next few years, but the investment they’ve made into PITCHf/x has to show that it can pay for itself first.