Introducing pWAR and Using It to Predict Who Wins Cy Young
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Who will win the AL and NL Cy Young Awards? In this analysis, I’ll introduce a new cumulative win value statistic, Paraball Wins Above Replacement, or pWAR, in order to identify the most deserving candidates.
The pWAR metric incorporates a pitcher’s xwFIP and total innings pitched, with a baseline xwFIP of 5.50 representing "replacement level." This threshold, set at the 3rd percentile for all pitchers with a minimum of 40 innings pitched, serves as a benchmark for evaluating performance relative to a potential AAA call-up.
First, here are the top 30 pitchers in the 2024 season to date ranked by xwFIP:
Table 1: MLB xwFIP leaderboard for 2024 (minimum 40 innings pitched)
As has been the case throughout the season, Mason Miller has a sizeable lead in the league-wide xwFIP rankings, with an xwFIP of 1.97, more than a half point better than his closest competitor. He’s followed in the top five by four shut-down relievers; Kirby Yates, Griffin Jax, Josh Hader, and Jeremiah Estrada.
The top 30 starting pitchers, with minimum 14 starts and 40 innings pitched, are listed in Table 2 below.
Table 2: Top 30 Starting Pitchers in 2024, ranked by xwFIP (minimum 14 starts and 40 IP)
After a resurgent second half of the season, Blake Snell has cracked to the top five starting pitchers, joining leader Tyler Glasnow, Paul Skenes, Garrett Crochet, and Chris Sale.
How Does the Overall Leaderboard Look if We Sort by pWAR?
The 30 most valuable pitchers according to pWAR are listed in Table 3.
Table 3: The 30 most valuable pitchers in the MLB, according to pWAR
Tarik Skubal leads the AL and the majors with a 4.2 pWAR, ahead of Logan Gilbert by 0.4, Garret Crochet by 0.5, and Corbin Burnes by 0.6. The first time Skubal popped on my radar was when I introduced xwFIP this past offseason. In the first version of xwFIP (before the inclusion of HR/FB rate logic to determine xHR), Skubal ranked second among all pitchers in 2023 xwFIP and first among all starters by a wide margin. If he can avoid a disastrous start in September, Skubal is poised to capture the AL Cy Young in addition to the possibly spectacular AL Triple Crown and MLB Triple Crown.
With Tyler Glasnow on the Injured List, Chris Sale is the front-runner to capture the NL Cy Young with a 4.1 pWAR, ahead of Dylan Cease by 0.5, Zack Wheeler by 0.6, and Paul Skenes by 0.9. Sale currently leads the NL in wins and ERA and trails Cease by just four strikeouts in his quest to grab the NL Triple Crown.
Mason Miller has the highest pWAR of all relievers with 2.0, but only ranks 48th among all pitchers given his limited innings pitched as a closer (in addition to a short IL stint). His ranking highlights how even the most dominant relievers are not able to add as much value as the best starting pitchers over the course of the regular season. Although relievers are a long shot to win Cy Young, they are very much in play for post-season series MVP awards, in which their combination of pitching a higher percentage of their teams’ innings in the playoffs along with the leverage of the game situations upon which they enter can push them ahead of starters in value.
