Throughout the baseball season, fantasy players must pay attention to three aspects of their starting pitchers: their skills, who they pitch against, and where they are pitching. The most important aspects are the skills the pitcher has, as these directly correspond to their peak potential and stability throughout the season. Pitchers can tweak their pitch mix or improve their velocity to alter their skills output, which is within their control.
However, the other two aspects can be just as important for a pitcher in the fantasy season. It’s why the “streaming pitchers” concept exists and there are daily articles about starting pitcher matchups. An intriguing pitcher can easily be benched when they have a start in Colorado or have to face a tough Atlanta offense. But the second the season ends, the importance of matchups disappears. Pitcher discourse reverts entirely to skills, and while it makes sense (schedules obviously don’t carry over year-to-year), the matchups can hinder the true skills of a pitcher.
Was a small sample size ruined by two tough starts? Or did someone get a nice run of opponents that gave them more shine than they may deserve? The following analysis looks at both who pitchers faced and where they played to see which players and teams were impacted the most.
The Data
I looked at the top 100 starting pitchers based on 5×5 earned value and filtered out the relievers who made the list as openers or siphoned a large amount of wins.
With that group of pitchers, I took their opponent’s OPS against that pitcher’s handedness as well as the park factor for the home stadium for each game. I calculated Z-scores for both OPS and park factors to create a composite matchup score. The Z-scores were also calculated on the team and division levels.
The Toughest Schedules
The top of the list for toughest schedules is dominated by lefties, as the league does better against lefties than righties overall by 10 points of OPS (.741 vs. .731). However, the handful of names at the top stand out as significantly worse matchups than the rest of the pack.
Chris Sale is a standard deviation above the next pitcher and almost two standard deviations above the 7th ranked pitcher. Sale suffered from making 17 of his 20 starts at ballparks with a park factor over 100 (which is the average) and his home park, Fenway Park, is the second most hitter-friendly park with a park factor of 108. This gave Sale the most difficult schedule by location by a longshot.
He also had the 8th highest OPS against, with opposing lineups hitting .746 against lefties. Sale ended the year with an underwhelming 4.30 ERA, but the tough schedule helped him underperform his 3.80 FIP.
Two other Red Sox pitchers make the list, emphasizing how tough pitching in both Fenway and the AL East is.
Another standout on this list is Reid Detmers, who faced the most difficult lineups throughout the year. His .754 OPS against ranked number one, as he got the Rangers four times, the Astros three times, and the Dodgers twice. Those teams all ranked top 5 in OPS against left-handed pitchers. Detmers was also a reverse splits pitcher in 2023, lefties slashed .294/.378/.504 against him while righties only slashed .236/.320/.373.
The Easiest Schedules
On the easier side of schedules, there are similar themes that emerge. Teams with pitcher-friendly parks and easier divisions have a handful of pitchers who got the best run of games in 2023.
Drew Rasmussen had the easiest schedule in 2023 but was limited to just 44.2 IP before going down with a UCL injury. His teammate, Zach Eflin, came in second and Aaron Civale, who was traded to Tampa Bay from Cleveland, ranked fourth. Although they pitched in the AL East, Tropicana Field is the 5th most pitcher-friendly park in baseball.
The most pitcher-friendly park, T-Mobile Park, helped put four Mariners in the top ten. Seeing upper-echelon arms such as Luis Castillo or Logan Gilbert get a boost from their matchups can make them significantly more valuable over the course of the season. Castillo outperformed his FIP by almost 50 points and Gilbert outperformed his FIP by 12 points. It is not a direct correlation, but helps get ERA luck.
The last two teams to see entrants into the top 10 are Guardians and Twins, who both got to face off against weaker AL Central offenses more often than anyone else.
Team Level Stats
This study intrigued me because of the new balanced schedule, and I (and many others) were unsure how much these new schedules were going to impact pitchers on both ends of the spectrum. Were the teams in both tougher and easier divisions going to regress toward the mean?
While I already alluded to the Guardians and Twins benefitting from the AL Central, it is a tight band between the easiest and toughest schedules purely by opponent’s OPS. The Angels had the worst luck with a .741 OPS and the Twins had the best with a .720 OPS, but it’s only a 21-point difference between the two.
Divisions still make a difference, but teams do not reap the full rewards of a weak division and are not as battered by a good division as they used to be.
Two main themes stand out: the NL East was (unsurprisingly) a gauntlet for opposing pitchers and both of the Central divisions are notoriously weak (mainly the AL Central). The per-division park factors do not mean too much, but the NL Central does have the hardest slate of stadiums to play in.
When taking into account the park factors and opponents, the best and worst teams to pitch for are largely understandable.
For the five teams with the worst schedules, four make sense and there is one anomaly. Cincinnati and Boston both played half their games in launch pads, while the Phillies and Braves both had to play in the tough NL East (despite being two of the better offenses in the division).
The Royals stand out on this list because they played in the abysmal AL Central. Their home park surprisingly played slightly hitter-friendly this year, but they also were on the wrong side of many of their matchups.
The Red Sox and Royals were over two standard deviations above the average team, but the rest of the pack was tightly bunched up. Those who just missed the top five were the Angels, Pirates and Giants.
On the easier side, more teams separated themselves from the pack.
Four teams were two standard deviations above the mean: the Mariners, Twins, Tigers, and Rays. The Mariners have the benefit of their stadium and both the Twins and the Tigers played a softer AL Central schedule. The Rays had a slight boost from their home stadium but mostly benefitted from facing an AL East division that was only league-average against RHP.
Takeaways
In a vacuum, there is no inherent value to using last year’s schedules when analyzing for next year. However, it can be useful for understanding top-line stats for certain pitchers who performed or underperformed due to a tough slate.
It is also a good reminder that divisions can still have a massive impact on pitcher performance, despite the balanced schedule. Although rosters will change going into the new season, getting an understanding of pitcher matchups will continue to be critical for pitching success in fantasy baseball.
Photo by Scott Winters, John Cordes, Kiyoshi Mio | Icon Sportswire
Adapted by Kurt Wasemiller (@KUWasemiller on Twitter / @kurt_player02 on Instagram)