Strength of Schedule at the All-Star Break

Over the last twenty years, MLB implemented a number of changes to the playoff structure and schedule. Among these, interleague play and the wildcard are the most noticeable to the typical fan. One change that can be overlooked is the unbalanced schedule, which with the advent of year-long interleague play in 2013 has become even less uniform between teams than before. Given that the schedule could have an impact on the pennant races, particularly wildcard races between teams from different divisions, a high-level view of each team’s remaining strength of schedule is in order.

First, a technical note: the strength of schedule figure (SOS) is expressed on a scale where the average SOS will be 100; values greater than 100 indicate a more difficult schedule. The SOS figure is the average rating of the team’s remaining opponents, weighted by games played. Home field advantage is not taken into account—three remaining games against Boston will count the same whether they are to be played at Fenway or at the opponent’s home stadium.

The ratings that feed the SOS estimate follow a similar scale and are based on a team’s actual win-loss record and Pythagorean win-loss record weighted equally, then regressed by adding 69 games of .500 baseball to the team’s record. For example, a team that is 50-40 with a 48-42 Pythagorean record would be treated as a 49-41 team, then 34.5 wins and losses would be added, resulting in a 83.5-75.5 record for the purpose of the ratings. Each team’s record is adjusted for its mix of opponents, then the process is repeated for several iterations until the ratings for each team stabilize. For a full explanation of how the ratings are calculated, please see this article.

While the focus of this article is the strength of schedule estimates, it wouldn’t be any fun to let this opportunity go by without examining the underlying team ratings themselves:


The strength of the AL East is readily apparent as all five teams boast ratings greater than 100, including Boston’s major league best 130. Each of the other AL divisions have two teams which are rate higher than the division leader in two of the NL divisions. The weakness of the National League West is apparent from the raw standings, in which only Arizona is above .500 at the All-Star Break, but adjusting for Pythagorean and strength of schedule does not make the performances of its members look any better.

The next set of tables shows three SOS figures for each team, all based on the rating of each team displayed in the previous table. The first, “To Date” is the team’s SOS as of the All-Star. The second, “Remaining” is the team’s SOS after the All-Star Break, based on the current rating of each team. The third, “Total”, is the team’s overall estimated SOS for all 162 games. As you peruse the figures, keep in mind that a team’s SOS is somewhat dependent on its own quality. It is quite likely that the dominant team in a division will have the lowest SOS, as they will play a large number of games against their weak divisional opponents, while those other teams SOS will be driven up by playing the dominant team.


Based on these estimates, the schedule does not figure to play a large role in the AL East race, as the contenders will all face roughly the same level of competition. In the AL Central, the top two contenders have easier schedules the rest of the way, but neither figures to gain much of an advantage in their race unless the Royals get back into contention. A similar situation is present in the AL West for Oakland and Texas.


In the NL, Atlanta’s remaining schedule is even easier than what they have played so far, and the Braves project to have the lowest remaining and total SOS. The Braves’ schedule fortune extends to interleague–while they faced play three AL team’s with ratings of greater than 100, only one of those series has yet to be played (Cleveland). The top contenders in the Central and West face roughly comparable schedules to one another.

Where SOS may come into play is in the wildcard races. The Indians and Rangers/A’s figure to benefit relative to their Eastern wildcard foes based on their easier schedules, while any teams from the NL East or West that make a run at the three Central leaders for the wildcard have slightly easier remaining dockets. Of course, as the season progresses, the quality of a team is not a constant, so estimates of SOS at this date may not reflect the actual caliber of opponent faced down the line.

While compiling this data, a few miscellaneous quirks of the schedule stood out:

  • There are fairly large discrepancies in the number of remaining intra-division games at this point. There are still 102 AL Central contests to be played, while at the other extreme only 70 NL West matchups remain. Overall, 277 intra-division games remain in the AL while 256 remain in the NL.
  • The Tigers and White Sox will be seeing a lot of each other, as they have played the fewest games to date of any division opponents (three) and thus have the highest number remaining (sixteen, as all teams play nineteen games against each divisional opponent). Detroit also ties for the second-most games remaining against an opponent as they still have fourteen to play with Kansas City (St. Louis and Pittsburgh also have fourteen remaining engagements). One might think that Detroit’s heavy dose of Chicago and Kansas City would benefit Cleveland, but the Indians still have ten meetings to go with the White Sox and thirteen with the Twins.
  • The White Sox lead MLB with 47 remaining intra-division games, meaning they play just 23 more outside the division. The Rockies have the fewest remaining with just 24 (precisely six against each NL West foe).
  • SOS is fairly constant for teams within the same division; while obvious differences exist in interleague opponents and there are slight differences in distribution against intraleague opponents, most of the discrepancies that do exist can be attributed to the quality of the teams themselves. Schedule can be a very significant factor for teams in different divisions, however. The SOS ratings imply that Milwaukee’s average opponent (101 total SOS, highest in the NL) would win approximately 52.3% of the time against Atlanta’s average opponent (92 total SOS, lowest in the NL). While this figure is inflated by the disparate quality of the Brewers and Braves themselves, it is a difference of 3-4 wins over a 162 game schedule. While this is the extreme end of the spectrum, strength of schedule could very well tilt a tight wildcard race between, say, Oakland (100 remaining , 101 total SOS) and Baltimore (107 remaining, 106 total SOS).

Photo by Keith Allison


Patriot is an Ohio native and a proud alum of The Ohio State University and has been a sabermetric enthusiast for nearly as long as he's followed baseball. As an Indians fan, he misses Grady Sizemore, Manny Acta, and Steve Reed, but not Jim Brower. He also follows thoroughbred racing and occasionally pretends that he knows something about it.