Checking in on the Cubs' Playoff Odds After the London Series

Two models of Playoff Odds projections dominate the national conversation: those on FanGraphs and Baseball Prospectus. On each, the Brewers dominate the Cubs in terms of likelihood to win the NL Central, and neither gives Chicago much chance to claim a Wild Card berth. As the team has heated back up recently, though, their odds have steadily risen--especially according to FanGraphs.

Baseball Prospectus's PECOTA projection system has been more pessimistic about the Cubs since before Opening Day, and that pattern persists, though the gap is small. BP gives them a 19.2-percent chance to reach the postseason, including a 16.5-percent shot at taking the division title. That model does have the Cubs as a clear second-best in the division, though, whereas FanGraphs sees the Reds as a legitimate, essentially equal contender. Obviously, since the Reds are currently leading the division, there does seem to be a kernel of truth to that.

At bedrock, though, the two models say the same thing. The Cubs are not the favorites in the division, thanks especially to their dreadful stretch of play from mid-April through the beginning of June, but they're viable, thanks to a solid foundation of talent and the weakness of their division. These projections are rooted not only in their record, but in their roster and the talent those systems see in it.

There is one other robust Playoff Odds engine out there, though. At Baseball Reference, they don't look at projections and roster composition. Rather, they use a rolling sample of a team's last 100 games played (even if it spans seasons) and adjustments for strength of schedule to project future performance. The system accounts both for opponent strength over that 100-game sample and for the strength of schedule for the balance of the season, and simulates the remaining schedule 1,000 times each day to come up with Playoff Odds.

In that system, the Cubs aren't fighting with the Reds for second place, or trying to get above 25 percent in terms of total chances to reach the postseason. In the Baseball Reference system, the Cubs are the division favorites.

By this system, the team is just on the right side of a coin flip to win the division, and will still have some chance of winning a Wild Card if they miss out on that. It's certainly a system that favors the Cubs in ways that could feel meaningless. Of their 100-game sample, nearly a quarter is the final stretch of last season, when they went 16-8, in a weird and low-pressure environment. That boosts them significantly, and so does the fact that the system is based solely on recent performance, rather than on projections at an individual level. Every projection system is somewhat skeptical that Marcus Stroman and Justin Steele are this good, but this system is just looking at their results. Ditto for Christopher Morel.

There are some reasons to doubt the utility of this kind of system, but there are also some reasons to think the Cubs are given short shrift by some modern projection systems. On balance, it feels like the true chances they have of reaching the playoffs lie somewhere between the numbers given by the two types of system, but that could just be cognitive biases at work.

At the very least, getting hot for the last two-plus weeks has positioned the Cubs to view themselves as buyers ahead of trade season. Whether it's an outside chance or a very good one, they clearly have a shot at winning this tepid divisional contest. The next fortnight will really illuminate things, though, and should clarify a lot of things. By the time that stretch is over and the All-Star break comes, the Cubs will no longer be leaning much on last season's strong finish in the Baseball Reference model. They'll also have played four more games against the Brewers, so we should have a better idea of which team is better. 

The Wild Card odds are especially interesting, though, and the first series after their English holiday will shine a spotlight there. According to PECOTA, the Cubs' Playoff Odds actually rose yesterday, even as they lost. Their own loss and wins by the Brewers, Phillies, Marlins, and Diamondbacks were outweighed by losses by the Mets, Reds, Pirates, Dodgers, Padres, and Giants. In the more balanced schedule environment and with so many teams making the playoffs, the Wild Card races really open up, and they do it early.

The Phillies come to Wrigley Field Tuesday night. That series, between a 40-37 team and a 37-39 one, will be an important test of the Cubs' mettle. By the weekend, we'll have another valuable set of data points to inform estimates of the team's Playoff Odds, even though there will still be much uncertainty, and even disagreement between models.