Finding Above Average Fastballs

I am huge proponent of the pitch type work which has led to the Arsenal Score here are FanGraphs. One possible issue with pitch type data is a reasonable amount of data needs to be collected before any conclusions could be draw. I am going to take it a step further today and look for MLB ready fastballs knowing just the pitcher’s velocity and break. Just knowing how the pitch’s speed and trajectory, some conclusions can be drawn on how the pitcher will perform in the future.

This past summer, I found how to estimate a pitcher’s fastball ground ball (GB%) and swinging strike rate (SwStr%) knowing just the velocity and break. The ground ball rate was the same for all pitches while the swinging strike rate varied a bit. Well, I went into meld/average mode to come up with a method to find a simple way to determine how productive a fastball may be knowing its current break and speed.

Here are the estimated swing strike and groundball rates using just speed and vertical break. Green means an above average pitch and red is below average.

Vertical Break GB% Velocity SwStr%
12 28.6% 100 8.7%
11 31.2% 99 8.4%
10 33.8% 98 8.0%
9 36.4% 97 7.7%
8 39.0% 96 7.3%
7 41.6% 95 7.0%
6 44.2% 94 6.6%
5 46.8% 93 6.3%
4 49.4% 92 5.9%
3 52.0% 91 5.6%
2 54.6% 90 5.3%
1 57.2% 89 4.9%
0 59.8% 88 4.6%

Here is both charts combined (X is good).

Velocity
  100 99 98 97 96 95 94 93 92 91 90 89 88
12 / / / / / / / /          
11 / / / / / / / /          
10 / / / / / / / /          
Vertical 9 / / / / / / / /          
Break 8 X X X X X X X X \ \ \ \ \
7 X X X X X X X X \ \ \ \ \
6 X X X X X X X X \ \ \ \ \
5 X X X X X X X X \ \ \ \ \
4 X X X X X X X X \ \ \ \ \
3 X X X X X X X X \ \ \ \ \
2 X X X X X X X X \ \ \ \ \
1 X X X X X X X X \ \ \ \ \
0 X X X X X X X X \ \ \ \ \

I fudged the overlapping zones to have more pitchers in the good area than the others. It is better add a pitcher than remove one since some values can be right on the edge. For this chart I would concentrate on two zones. The obvious zone where there is overlap between the two traits. The other is where there is no overlap. The reason for liking the overlapping area is simple … pitchers can get by if their fastball generates just a high number of ground balls and strikeouts. If the pitcher can’t do either, he won’t last long in the league.

Now, how about putting the chart to work. I got the Arizona Fall League (AFL) pitch stats from MLBfarm.com and looked to see which fastballs fall into the overlapping zone. In the AFL, the pitchers generally are not on par with the hitters. Most pitchers have met their seasonal pitch limits by the time the AFL comes around and don’t get sent to Arizona. The league is filled with pitchers who have missed time because of  injury or are just organizational fillers. There is going to be far more below average than above average pitchers.

After looking over the data, four pitchers make the velocity and vertical break thresholds.

Name Break Velocity eGB% eSwStr%
Reed, Jake 5.6 93.6 48% 6.4%
Sherfy, Jimmie 7.2 96.1 40% 7.3%
Gott, Trevor 7.4 93.0 40% 6.3%
Smith, Chad 7.8 93.5 39% 6.4%

Here is a little info on each.

Jake Reed (Minnesota) – He has been climbing up the prospect rankings and got some love from our own Kiley McDaniel a couple of months ago.

It’s hard to believe but Reed was a starter at one point in college, but that helped his formerly usable changeup now flash average, a pitch most guys like this don’t have. Reed has been sitting 94-97 mph in the AFL, his slider flashed above average and I still think he’ll move quickly as I stated on the Twins list, but now the upside is a little higher, likely as a setup man, like Burgos.

Jimmie Sherfy (Arizona) – Kiley currently has Sherfy as #16 in the Diamondbacks organization and wrote this about him:

More than one scout described Sherfy as “f’ing weird” with his high effort delivery and high-energy temperament on the mound, but he’ll flash two plus-plus pitches at times. One scout said he saw 95-97 and a 60 slider in Low-A that would’ve gotten big leaguers out, then saw nothing but 30 grade sliders in another outing. A second scout said he saw the slider as a 70 when Sherfy was 96-98 mph but the mechanics are so ugly, you need to rush him to the big leagues before that gun is out of bullets. He flies open at times and will throw the slider too much with a high maintenance delivery, but there’s something here.

Trevor Gott (Angels) – Seems like organizational filler with the chance to be a bullpen arm if he can get some control. Here is a take from Chris Rodriguez on Gott from Baseball Prospectus.

Gott has a super quick arm that can touch the high 90’s. He’s already in Double-A following an appearance in the A+ all-star game where he reportedly sat 94-98. The plane on his fastball isn’t great because of his size, but the movement is plus-plus and I love the way he challenges hitters with it. Looks like he can make a contribution to the Padres bullpen sometime next season, with a very good fastball/curveball mix that plays well at the backend.

Chad Smith (Tigers) – He was able to throw 11 innings for the Tigers this past season. Off his fastballs, only 12 were put into play and his GB was way below average. We should expect it to go up as his sample size increase.

Besides these above average pitchers, a bunch of pitchers didn’t rate above average in either category.

Jason Adam, Brandon Alger, Matt Anderson, Lisalverto Bonilla, Matt Brazis, Zach Cates, Gerardo Concepcion, Zach Cooper, Caleb Cotham, Scott DeCecco, Ryan Dennick, Anthony DeSclafani, Ryan Doolittle, C.J. Edwards, Carlos Gonzalez, Nelson Gonzalez, Drew Granier, Brooks Hall, Thomas Harlan, Ryne Harper, Mitch Harris, Julian Hilario, Nate Hyatt, Tyrell Jenkins, Aaron Kurcz, Mitch Lambson, Stephen Landazuri, Matt Lollis, Nick Maronde, Josh McElwee, Blake McFarland, Adam Morgan, Sean Nolin, Chris O’Grady, Jefferson Olacio, Roberto Osuna, Tyson Perez, Chris Perry, Tanner Peters, Reid Redman, Felipe Rivero, Angel Sanchez, Mark Sappington, Jaime Schultz, Sam Selman, Grant Sides, Arik Sikula, Blake Smith, Burch Smith, Scott Snodgress, Ethan Stewart, Michael Strong, Daniel Stumpf, Mike Thomas, Ashur Tolliver, Wei-Chung Wang, Ali Williams, Madison Younginer,

Sean Nolin (A’s) – His name sticks immediately out. He was one of the piece who went to the A’s in the Josh Donaldson trade with the Blue Jays. His velocity just misses the cut off, but his fastball doesn’t drop at all. In the minors his GB% was only at 38%, so he may have some home run issues. These possible home runs may be why Toronto didn’t want him in their home run happy park and Oakland did want him for their huge park.

I don’t like saying a pitcher is good or bad based off a small sample. What the small sample can do is give some expectations. These expectations can be exceeded or not, but it is a start in evaluating pitchers. With fastballs, a person can know if the velocity or break is enough to generate league average GB% or SwStr% rates. If the fastball doesn’t meet these requirements, the pitcher better bring something more to the table. Great secondary pitches. Outstanding command and/or control. Good deception. Sometimes in fantasy baseball a quick decision has to be made with little information and hopefully I can help you make that decision with pitchers.





Jeff, one of the authors of the fantasy baseball guide,The Process, writes for RotoGraphs, The Hardball Times, Rotowire, Baseball America, and BaseballHQ. He has been nominated for two SABR Analytics Research Award for Contemporary Analysis and won it in 2013 in tandem with Bill Petti. He has won four FSWA Awards including on for his Mining the News series. He's won Tout Wars three times, LABR twice, and got his first NFBC Main Event win in 2021. Follow him on Twitter @jeffwzimmerman.

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Grant
9 years ago

Does looking at the curvature (sharpness of break) of a pitch have any significance on the quality? It could be calculated from pitch f/x data, no?