By @Inside Pitch, AngelsWin.com Senior Analyst

Most people here will likely want to skip this, it's stat nerd heavy, but if you are interested in stuff like that you'd be well served to read this excellent article at FG...

https://library.fangraphs.com/pitching/stuff-location-and-pitching-primer/

This post leans heavily on the information in this article but for anyone not wanting to read the long form or that doesn't want to have to look at a bunch of graphs you can basically focus on these three excerpts/summaries on the three major pitch modeling components.

Stuff+

Stuff+ looks only at the physical characteristics of a pitch. Important features include, but are not limited to, release point, velocity, vertical and horizontal movement, and spin rate. A pitcher’s secondary pitches are defined based on their primary fastball — with “primary” defined by usage in an outing — and so are judged by velocity and movement differentials along with raw velocity and movement numbers. The model also includes “axis differential,” a statistic that attempts to describe the difference between the movement expected by spin alone and the observed movement affected by the phenomenon described as seam-shifted wake.

Stuff+ was trained against run values, so even if the research community is divided about how much a pitcher can control weak contact, the model includes an inherent nod to the possibility that they do possess some of that ability.

Location+

Location+ is a count- and pitch type-adjusted judge of a pitcher’s ability to put pitches in the right place. No velocity, movement, or any other physical characteristics are included in the statistic. A breaking ball should go to different parts of the strike zone in 2-0 and 1-2 counts, and Location+ captures that phenomenon. Stringer-based command statistics that attempt to judge what a pitcher was intending to do with each pitch do not add predictive value to those models, so Location+ only looks at actual locations and implicitly assumes the intent is generally the same across the league in certain counts with certain pitches.

Pitching+

The overall model, Pitching+, is not just a weighted average of Stuff+ and Location+ across a pitcher’s arsenal. Rather, it is a third model that uses the physical characteristics, location, and count of each pitch to try to judge the overall quality of the pitcher’s process. Batter handedness is also included in Pitching+, capturing platoon splits on pitch movements and locations.

So the short version of all the above..  The point of it all is to measure movement/pitch type, location/pitch type, and how well a pitcher does at doing both

If you have ever wondered why a guy that throws so hard gets lit up so much -- pitch modeling data is where you want to look.  If you wondered how guys can be coasting and all of a sudden a single baserunner can wreck it all -- again, pitch modeling is where you want to look.

Years ago I waxed poetic about Zach Wheeler despite what the ERA was because WATCHING him pitch it was obvious he was better than his numbers.  For a couple years I mentioned trading either Adell or Marsh in exchange for George Kirby, again because watching him throw.  Now thanks to pitch modeling it's easier to argue that Pitcher A, should be better or will do well in the future.,

Wheeler ranks number 2 in MLB in Pitcher+, Kirby 3rd among MLB qualifiers.

So what does this have to do with Lorenzen?

Last we saw him, he was getting lit up the second half of 2023 -- he ended the season with an ERA over 5.50 after joining Philly and was dropped from the rotation -- awful except maybe it was just fluke results, fatigue, or simply bad pitch selection after swapping teams.

Stuff + is again the weighted results of every pitch thrown by every pitcher.