Your 2023 Giants: Harrison's Comparisons

I’m giving thanks for Kyle Harrison.  Kyle Harrison was the premier prospect for the Giants in 2023, and he did not disappoint, getting over early struggles to force his way into the majors. While his MLB ERA and long-ball weakness was not good at all, his overall stats - hits, strikeouts, walks - were excellent for a new prospect, and reducing the long ball to normal standards would mean he's at least an average starting pitcher. 

He is hopefully the ace we need to lead us during this decade. His stats in the minors remind me of Lincecum, particularly his dominance of hitters. And he came in not knowing hitters, but striking them out at elite levels, while not walking many.  With him and Webb atop our rotation, we’ll be competitive for a long while, health permitting.

In this post, I want to see how similar aged pitchers with similar MiLB pitching line stats did in prior seasons, to see how these pitchers with similar results did in the majors subsequently.

ogc thoughts

Kyle was a fast learner.  He reached AA by age 20 (typically the best prospects - college, high school, or IFA -  reach AA by age 22), and he did really well there, with 3.11 ERA, 1.18 WHIP, 4.2 BB/9 (only really bad), but 13.6 K/9, which is really good, making his K/W ratio 3.26, which is good. 

He wasn’t as good in AAA, but those stats were affected by the use of robo-umps calling the strike zone in AAA, which threw a lot of pitchers off.  A good sign of this was his performance in the majors. Here was his key pitching stats in AA and MLB:

• AA:    3.11 ERA, 1.18 WHIP, 4.2 BB/9, 13.6 K/9, 3.26 K/W
• MLB: 4.15 ERA, 1.15 WHIP, 2.9 BB/9, 9.1 K/9, 3.18 K/W

A high walk rate is not ideal (his minors suggest problems; but 2.9 BB/9 in the majors is good), but does not diminish a prospect’s potential as long as they strike out enough to keep his K/W ratio at 3+, which Kyle does.  

It’s actually better relative to a pitcher with less walks and thus less strikeouts, keeping the K/W ratio the same. Think of it this way: adding a walk per 9 means adding 3 strikeouts (assuming 3+ K/W ratio), which means roughly one less hit because BABIP is .300 mean, which altogether means that this pitcher replaces a hit with a walk, by increasing walks and strikeouts at a 3:1 ratio or above.  I figured this out long ago analyzing how it might work for Jonathan Sanchez, given his high strikeouts and high walks rates.

Comparables

Because the pandemic killed the 2020 minor league season, I had to go back to 2019 to find pitchers who are comparable and had MLB experience.

In AA Eastern League 2019, there was no 20 YO among the league leaders in ERA. There was only two really young pitchers who had similar walk, strikeout and K/W ratio:

• Matt Manning: 21 YO, 2.56 ERA, 0.98 WHIP, 2.6 BB/9, 10.0 K/9, 3.89 K/W
• Tarik Skubal:  22 YO, 2.13 ERA, 1.016 WHIP, 3.8 BB/9, 17.4 K/9, 4.56 K/W

Both were good in the majors at 3 years of their AA performance:

• Manning reached the majors, took some time to figure things out, then was good ages 24-25, with 3.51 ERA, 2.6 BB/9, 6.3 K/9, 2.45 K/W
• Skubal reached the majors, took some time to figure things out, then was good at age 25 and great at age 26, overall 3.87 ERA, 2.5 BB/9, 10.0 K/9, 4.04 K/W

There was another prospect who did well in AA, 2018-19:  Logan Webb. Between the two seasons (21-22 YO seasons), he had a 2.88 ERA, 1.306 WHIP, 2.9 BB/9, 9.1 K/9, 3.17 K/W.  He had some initial issues in the majors, but has been great ages 24-26, as we know.

Of course, every prospect is different, and the success of others is no guarantee that Harrison will likewise succeed. Still, they exhibited similar talents at a same level/league, and was able to develop into good pitchers (so far), after some growing pains.  

Plus, Harrison did it at a younger age than any of these, as he was only 20 YO in AA.  And only 22 YO next season, and thus only 2 years past AA, when the players above blossomed 3 seasons after AA success, so he might not blossom until 2025. Hopefully he’s a quick learner.