Pirates+; Fangraphs Stuff+ Pitching Models

A look at Fangraphs Stuff+ model shows Pirates have some intriguing bullpen options

Photo Credit: Ryan Palencer

It’s been a minute since I’ve had spare time to dissect some analytics we’ve sought to understand further. The last article I wrote was an opener – pun intended – into some of the newer pitcher data of Vertical Approach Angle (VAA) and Horizontal Approach Angle (HAA).

It centered around the success of flatter four-seam fastballs with ride and steeper sinkers. At this juncture, an understanding of what values of HAA show a greater chance of success hasn’t been developed. Still, Alex Chamberlain should hopefully have a deeper dive into HAA coming out sometime soon.

As for now, I’d like to look into various models and how individual Pittsburgh Pirates pitchers fared - starting with Kyle Nicolas.

Remember Robert Stephenson? The next pitcher in line, who seems to struggle, goes to the Tampa Bay Rays and succeeds. My “aha” moment was when I looked at Fangraphs Stuff+ model, and Stephenson had by far the best Stuff+ -- though only 14.0 IP – of 130, with David Bednar second in line at 118 Stuff+ in 67.1 IP. That is, until you drop the qualified innings.

With 5.1 IP, Nicolas had an overall Stuff+ of 130. His Fastball Stuff+ was 124, slider at 137, and curveball at 134. Nicolas paired that with a Pitching+ of 100 (average) but a below-average Location+ of 91.

Looking at Chamberlain’s data tables, you can see likely why Nicolas’ fastball saw such success, as it had a VAA of -4.2 degrees, with -4.0 being optimal. Take out his rough debut, and he struck out seven batters to only two walks in five innings. He’s going to be an arm to keep an eye on come next season.

Just after Bednar’s 118 Stuff+ is Colin Holderman with 114, two other young relief arms are Tied with him: Hunter Stratton and Colin Selby. There’s a bit of a stark contrast between the two.

Selby relies on a sinker that he averaged 96.6 MPH on and had a relatively flat approach angle for a sinker of -5.4 VAA. Selby's sinker had a Stuff+ of 106. His fastball was average at 100, a curveball of 109, and his slider had a 127. He struggled in the other areas, with a Location+ of 93 and Pitching+ of 97.

Stratton relied on a four-seam that averaged 96.0 mph and a rather steep approach angle of -5.6 VAA. He also gets quite the rpm on his fastball of 2,567. His fastball Stuff+ was similar to Nicolas’ at 122, his cutter was 109, and 113 on his slider.

He excelled in other areas as well. He had a Location+ of 102 and Pitching+ of 104. For comparison, Keller had a Stuff+ of 104, Location+ 103, and Pitching+ 103. Bednar’s overall numbers were Stuff+ 118, Location+ 101, and Pitching+ 106.

As a whole, the Pirates excelled in one particular area. They had 18 pitchers — with 5.1 IP and above, including Nicolas — with a Stuff+ of 100 or better on their slider.

Nicolas has some areas for improvement, and the biggest question regarding Stratton and Nicolas would center around how their numbers trend throughout throwing 40-50+ MLB innings.