Strength of Schedule and the Pennant Races

No team plays a completely balanced scheduled over the course of a season. Some divisions, naturally, are better than others. Because intradivisional games account for roughly 40% of the league schedule, there is necessarily some irregularity in the strength of competition from club to club. Interleague play, which represents another 10% of games, also contributes to this imbalance. Given the sheer numbers of games in a major-league campaign, the effect of scheduling ultimately isn’t a major difference-maker. Talent and luck have much more influence over a club’s win-loss record. In any given month, however, scheduling imbalances can become much more pronounced.

Consider this: at the beginning of the season, just one team featured a projected gain or loss as large as three wins due to scheduling. The Texas Rangers were expected to lose three more games than their talent would otherwise dictate. Right now, however, there are eight teams with bigger prorated schedule swings than the one the Rangers saw at the beginning of the season — and those swings could have a big impact on the remaining pennant races.

To provide some backdrop, the chart below ranks the league’s schedules, toughest to easiest, compared to an even .500 schedule.

The Diamondbacks have a pretty rough go of it. Outside of five games against the Padres, the other “worst” team they play is the San Francisco Giants. They have one series each against the division-leading Astros, Braves, and Cubs along with a pair of series against both the Dodgers and Rockies. If Arizona were chasing these teams for the division or Wild Card, their schedule would present them with a good opportunity for making up ground. Given their current status, however, it just means a lot of tough games down the stretch.

At the other end is Cleveland. They don’t really need any help at the moment to secure the division, but with 19 of 32 remaining games against poor divisional opponents, nobody stands to benefit more from their remaining schedule than the AL Central leaders.

To show how the schedule affects our projections and the races with a little over a month to go, let’s take a look at the jumbled National League. Below we see the projected win totals for NL contenders.

We have the Cubs out in front, with the Diamondbacks leading a pack of five teams all featuring projected win totals between 88 and 89 games. The Rockies and Phillies fall not too far behind that. We know from the graph above that the Diamondbacks are facing the toughest schedule the rest of the way. The following table shows how that schedule affects their projected win total and their standing among others vying for a playoff spot.

The first column comes from the previous table, and you can find that information on our projected standings page. That column reflects projected wins based on talent alone, without accounting for schedule. The rest of the table comes from our Playoff Odds page, which does account for the remaining opponents. Once the remaining games are factored in, Arizona moves from projected division-winner and second-best team in the National League to sixth-best team and out of the playoffs entirely. The Brewers moved from just out of the Wild Card to qualifying for the NL’s one-game playoff. With rounding, the Brewers and Diamondbacks end up in a play-in game to get to the Wild Card. There is currently an 18.4% chance of a two-team tie for the second Wild Card with a 4.2% chance of a three-way tie and a 1-in-200 shot at four teams tied for the second wild card at the end of the year.

The National League is not the only race affected by schedule. This is what the AL East looks like after the schedule adjustment is made.

The Red Sox are in command of the division at the moment, but they’ve lost a few games on their lead of late. The schedule doesn’t dramatically affect the odds, but it does inch the Yankees a little bit closer. With six games remaining against each other, New York still has a shot at making things interesting down the stretch.

The American League West is currently closer in the standings than out East, with the Astros up 2.5 games* on the A’s, but the current projections have the division ending up at about the same spot as the Yankees and Red Sox.

Where the schedule creates a closer race in the East, it makes the gap bigger in the West. Making things even more difficult for the A’s is that, after this week, they play no more games against the Astros and therefore lack the opportunity to make up ground directly. As for the Mariners, their schedule is pretty neutral moving forward, but they do have the benefit of playing the A’s seven more times and have seven of their last 10 games against the Rangers. Seattle’s playoff chances aren’t promising, but they will be presented with the opportunity to make things happen.

Looking at some of the figures about, it might be difficult to tell why 0.6 wins matters when it comes to schedules. To hopefully help clarify the type of impact the schedule can theoretically make, I’ve listed a bunch of different pairs of teams, the difference in wins their schedules create between the two teams, and an equivalent player who is projected to have the same impact the rest of the season. By identifying the scheduling loss with a similarly valued player, we might get a more concrete sense of the type of loss teams are dealing with when it comes to the remaining schedule.

If the Dodgers and Diamondbacks had the same schedules going forward, but Arizona lost Paul Goldschmidt for the season, their current playoff odds might not change significantly. The difference between the schedules of the Braves and Phillies would be similar to the Braves losing their star rookie the rest of the way. Ultimately, the players on the field will decide their fates, but the remaining schedules have made some teams’ task more difficult than others.