21-03-2025
Pitching Season Rating: A new metric for grading starting pitchers in fantasy baseball
Spending the past week running correlations while learning new spreadsheet formatting techniques can only mean one thing — I desperately need the baseball season to start (on American soil). Before we kick off, another hat tip is in order for the fine men and women working behind the curtain here at The Athletic. In an age of saturated and generic content, very few pieces nowadays are dedicated to progenitorial work aimed at developing a new metric or idea. And it makes sense — most flop and wind up in the dustbin of fantasy history … but not this one (I hope).
Despite dedicating every winter to fantasy baseball research, there's seemingly never enough time to cover it all, especially when the eleventh hour hits. Consider my newest brainchild, Pitcher Season Rating (PSR), an invention out of necessity. We've all been there in the draft room. You're a few picks away in a snake draft with a handful of hitters in the queue until it's suddenly empty. When it comes to batters, the industry has created more than one all-encompassing stat for a shorthand comparison, whether it's Weighted Runs Created-plus (wRC+) or Weighted On-Base Average (wOBA). Granted, it doesn't fully account for our fantasy perspective, namely steals. However, it will almost always steer you in the right direction. But what about starting pitchers? ERA and WHIP are skewed by volume or lack thereof — and while wins and strikeouts account for quantity, they don't speak to the quality of innings pitched.
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Long story short, our backstory is now in place — the lightbulb went on, and PSR was born. There isn't a comparable shorthand to serve as a sufficient starting pitching descriptor, particularly for a fantasy-based perspective. I wanted something on a 1-100 scale (similar to Madden ratings) that can be looked at for quick yet fair fantasy season comparisons. The closest thing in existence would be auction value returns, but there are a few issues. For starters, not everyone speaks dollar-value lingo, but it also accounts for replacement value, which I ignored. I didn't incorporate the player rater into my calculations, but I did use it as a benchmark in my backtesting, and the high correlation (R=0.86) feels pretty encouraging for a first run.
(Sample from FanGraphs consists of all 271 starting pitchers with at least two games started and 10 innings pitched in 2024 so as to avoid openers)
Wins — The wonkiest of all pitcher stats, one sit-down at an auction calculator will open your eyes to each win's value. Only two SPs posted 18 wins in 2024, and it doesn't start consolidating there — just 32 SPs eclipsed a dozen wins last season. Since the stat exists in a vacuum, players like Cody Bradford and Trevor Williams get a major boost for earning a half-dozen dubs each in under 75 IP.
Earned Run Average — Ratios proved especially hard to weigh due to their dependence on volume. Shane Bieber didn't surrender a single earned run, but it seems disingenuous to rate it among the best fantasy seasons in the league at just 12 IP. Conversely, both Taijuan Walker and Johnny Cueto posted an ERA north of 7.00, but Walker's hurts much more across 74 IP as opposed to 11 IP. You get the point. If PSR ever does catch on in the industry, I look forward to improving its impact.
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WHIP — The same issues as grading ERA with a necessary curve applied to volume. Only 18 qualified SPs, by my parameters, hung a sub-1.00 WHIP in 2024, but more impressive perhaps is that four achieved it in over 180 IPs — Logan Gilbert, Tarik Skubal, Zack Wheeler, and Bryce Miller. Similar to ERA, Shane Bieber deserves some credit for a stellar 0.92, but I'm struggling to claim he had a fantasy season for the ages in just a dozen frames.
Strikeouts — Finally, a category that didn't require me to blow dust off my old statistics textbooks. Combining an element of quantity and quality, total strikeouts do the best job as a standalone descriptor — though the bar's extremely low given the circumstances. For reference, it's not until SP66 by PSR that a pitcher struck out fewer than 100 batters, and it was Gerrit Cole at 99.
Since the study includes all pitchers meeting my minimum workload requirements, a '50' grade doesn't properly represent the bland or average season by percentile for our purposes. Using the eye test, I think that needs to get bumped up to 60, where Matt Waldron (142.2 IP; 7 Wins, 4.79 ERA, 1.24 WHIP, 130 K) and Alec Marsh (128.0 IP; 9 Wins, 4.57 ERA, 1.25 WHIP, 122 K) finished. Pretty unremarkable, huh? If you're nodding yes, it probably means we're onto something.
12 starters earned +90 PSR in 2024 (SP1):
12 starters earned between 85-90 PSR in 2024 (SP2):
I can't list all 271 SPs here, so I made the entire 2024 PSR list (with 5×5 stats) available on a public sheet. If the industry finds this useful, thought-provoking or both, maybe we can revisit it at the All-Star break to track 2025 or in the offseason and go back a few years. Get in the comments below and let us know what you think!
(Top photo of Tarik Skubal: Julio Aguilar / Getty Images)
