40 games in: The Arizona Diamondbacks’ playoff odds

Another ten games in the book, so time to revisit the standings, the playoff odds of the various projection systems, and what history tells us has happened to previous teams with the Diamondbacks’ current record.

The last 10 games

Instinct suggests we should probably have done better. Not winning a series this month - especially against a relatively weak set of opponents - feels like a wasted opportunity. But it’s not as if too many other teams in the league have done much either: only the Dodgers and Cardinals went better than 6-4, and the Dodgers have always been seen as close to certs, so that won’t have moved the needle very much for them. Arizona did outscore the opposition by a 46-43 margin. They have one blowout loss (1-9 in Colorado), but picked up two blowout wins. The pair of one-run games, both against Pittsburgh, were evenly split.

The projection systems

• Baseball Prospectus: 37.3% (6.9% div, 30.4% wildcard)
• Fangraphs: 35.0% (3.8%, 31.1%)
• FiveThirtyEight: 38% (13%, 25%)

Prospectus ticks our chances up slightly, by 1.2%, while the other two systems drop our chances a little, by 3.9% (Fangraphs) and 1% (FiveThirtyEight). However, all of them agree that our division chances took a sharp beating. Fangraphs almost cut our odds in half - they were at 7.2% last tine - so that is an area where the Dodgers’ surge has had a significant impact. Fangraphs are also the only people who didn’t raise our wild-card odds, declining there, albeit by less than one percent.

If we look at the Fangraphs graph, the biggest uptick in the first 10 games was caused by the opening win in the Pittsburgh series, which increased our playoff odds by 5.2%. Conversely, the largest drop was a result of the final game at Coors Field, which decreased our chances by 5.8%. Overall, we have now dropped back into third place in the NL West, with the Rockies now seen as close to a 50/50 bet. That seems a little generous for a team with a run differential of +7, only good enough for seventh best in the National League.

Previous 40-game records

I’ve analyzed the results since 1998 of all 570 teams to this point, and whether or not they made the post-season. The chart below breaks down the records, and also lists the teams currently occupying each band in the 2017 standings. I used win percentage to decide their block, on an “at least” basis, e.g. you need at least a .600 W% to get into the 24-16 level.

The bar for any sustainable hope is gradually creeping up. Now, a win percentage of .400 or below, 40 games in, is all but impossible to overcome. Only two of the 162 teams to make the playoffs since 1998, started off by going 16-24 or worse: the 2005 Astros and the 2009 Rockies. There are seven teams currently in that situation, including both the Giants and Padres in the National League West. However, San Francisco have actually been playing their best baseball of the season, winning their last four in a row. It’s only the second time this year they’ve even won consecutive games. But after this series against Los Angeles, they then have to go on the road and face the Cardinals and Cubs, so this may well prove to be a false dawn.

The D-backs’ record under this methodology results in a significant bump, up to 43.6% from 31.4% at the 30-game mark. However, just as that estimate was likely on the low side, this feels a bit high, with a significant (17.7%) drop-off for just one win fewer. Still, we’ll keep doing as we have been doing, and combining all four methods, we get an average playoff chance for the Diamondbacks of 38.5%. This is a couple of percent up on the last check, but more by luck than good play, it seems to me. With home series against the Mets and White Sox, and road ones facing the Padres and Brewers, doing better than 5-5 the next time we report, seems almost required.