Ranking the Top Starting Rotations

March 15, 2018
 

Although this has been a slow MLB offseason by most standards, some of the moves have resulted in notable starting pitchers such as Yu Darvish, Jake Arrieta and Gerrit Cole moving to new teams. With Major League Baseball’s Opening Day just a few weeks away, we decided to rank baseball’s top starting rotations based on Bill James’ Starting Pitcher Rankings.

The Starting Pitcher Rankings are based on park-adjusted Game Scores. Each pitcher starts his career at a score of 300, and for every game he starts, 30 percent of his game score is added to 97 percent of his previous rating. If he pitches well, his score goes up, but if he pitches poorly or doesn’t start a game for an extended period, his score goes down. The numbers below are based on the sum of a team’s five highest starters in the Starting Pitcher Rankings as of today.

The top three rotations in baseball entering the 2018 season remain unchanged from the 2017 end of regular season rankings—the Indians, Nationals, and Cubs. The order has shifted from 2017, however, with the Cubs falling from first to third and the Indians and Nationals ahead of them, respectively. In the case of the Nationals, there is room for improvement as Edwin Jackson (313) is currently slotted as the fifth starter. Cleveland, meanwhile, will be hoping for a healthy season from Danny Salazar (413).

We see a lot of the offseason’s impact on the teams outside of the top two. Despite losing Arrieta (496) in free agency, the Cubs were able to maintain a top three rotation with the additions of Darvish (448) and Tyler Chatwood (402). Replacing Mike Fiers (392) with Cole (445) accounts for the Astros’ upward movement from the eighth-ranked staff at the end of 2017 to the fourth-ranked staff as of today.

Thanks to a late push from free agent Lance Lynn (406) and trade acquisition Jake Odorizzi (440), the Minnesota Twins are one of two newcomers to the top ten rotations. Odorizzi and Lynn rank as Minnesota’s second and fourth starters, replacing Bartolo Colon (378) and Hector Santiago (326). Free agents are responsible for the other new inclusion in the top ten, the Milwaukee Brewers. The Brewers added Jhoulys Chacin (414) and Wade Miley (384) this offseason and moved up six spots to enter 2018 as the 10th-ranked staff.

Note that these scores tend to favor pitchers who stay healthy and start consistently, so seasons interrupted by injury can throw off a pitcher’s score. For example, Noah Syndergaard (407) is the 64th-ranked starter overall after missing most of 2017 to injury, and Lance McCullers (375) is ranked 101st-overall and sixth on the Astros after being limited to fewer than 126 innings in three consecutive seasons. There is room for upward (or downward) mobility for these pitchers and others as 2018 unfolds.

The full list of team rankings can be found below.

Starting Pitching Staff Rankings
Rank Team Score   Rank Team Score
1 Cleveland Indians 2348   16 Philadelphia Phillies 1938
2 Washington Nationals 2326   17 New York Mets 1925
3 Chicago Cubs 2293   18 Detroit Tigers 1901
4 Houston Astros 2259   19 Baltimore Orioles 1899
5 Boston Red Sox 2241   20 Colorado Rockies 1872
6 Arizona Diamondbacks 2221   21 St. Louis Cardinals 1855
7 New York Yankees 2218   22 Tampa Bay Rays 1818
8 Los Angeles Dodgers 2209   23 Pittsburgh Pirates 1816
9 Minnesota Twins 2113   24 Atlanta Braves 1787
10 Milwaukee Brewers 2100   25 Chicago White Sox 1778
11 Toronto Blue Jays 2090   26 Miami Marlins 1736
12 San Francisco Giants 2054   27 Oakland Athletics 1721
13 Kansas City Royals 1983   28 San Diego Padres 1702
14 Seattle Mariners 1963   29 Cincinnati Reds 1647
15 Texas Rangers 1955   30 Los Angeles Angels 1641
 

Thanks to Mike Murphy of ESPN Radio in Chicago for this idea. The full list of 2017 Starting Pitcher Rankings can be found in the 2018 Bill James Baseball Handbook, available now at ActaSports.com. Daily updates of the Starting Pitcher Rankings can be found on Bill James Online throughout the season.

 
 

COMMENTS (6 Comments, most recent shown first)

nettles9
I think the explanation of the criteria used and what the list represents is very clear. I, me, myself and the guy in my mirror see no issues with this.
11:40 AM Mar 18th
 
jwilt
This may be the only source you'll find that has the Orioles with a reasonably good starting staff. They have three somewhat solid major league starters in the organization (Gausman, 4.68 ERA, Dylan Bundy 4.24, Andrew Cashner with FIP more than a run higher than ERA). They have Chris Tillman coming off a trainwreck of a season. And a mostly undefined 5th spot. No real starting prospects in the high minors, with Rule 5 candidates actually in contention to start. Yet, they're better than 11 other teams!
8:59 AM Mar 16th
 
Mike137
doncoffin wrote: "Differences of less than 2 s.d. are often thought not to be particularly meaningful."

The standard deviation to be used for that purpose is for the random error. Using the entire variation to compute the standard deviation implicitly assumes that all the variation is random. So that naturally leads to the conclusion that the differences are not meaningful. But it is just a circular result.
8:44 AM Mar 16th
 
OldBackstop
Predictive rankings seem to me to be problematic at the least and misleading at the worst for the example given, The injured Syndergaard (and Matz, and Harvey, and Wheeler).

It is weak to predict that a team that was one of the top staffs when healthy in 2015 and 2016, and one of the worst when decimated by injuries in 2018, will be a comfy median 17th in 2018.

A real predictive formula would have to consider....well, a shttload more...
2:55 AM Mar 16th
 
doncoffin
Because I am the kind of guy I am, I immediately calculated the mean (1980) and standard deviation (213.5) of this. Assuming we can use these as rankings (and I think Mike 137 is right, that's probably an invalid use of the data), the Indians are 1.72 s.d above the mean and the Angels are 1.59 s.d. below the mean. Differences of less than 2 s.d. are often thought not to be particularly meaningful. If that's the case, none of these differences are particularly meaningful. It's a certainty that we'd have to conclude that there is no meaningful difference between the top 8 teams.

So it's nice to have numbers to play with, but I certainly would not base any decisions or forecasts on this.

10:05 PM Mar 15th
 
Mike137
It strikes me that this is a misuse of the rankings, since those are not meant to be predictive. In a match up between two pitchers, the one with the higher score is not always the pitcher more likely to win, other things being equal. The reason is that pitchers are credited for durability and, to some extent, for how long they have been around. So the rankings are established value for individual pitchers. But I see no reason to assume that they are additive for a staff as a whole.
3:20 PM Mar 15th
 
 
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