20 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

After going 7-3 over their first ten games, the Diamondbacks regressed somewhat, posting an even record of the last ten. However, the majority of those contests were on the road, so this likely isn’t too unexpected. They scored a total of fifty runs over that time, while conceding forty-one, so could be considered unlucky to have a .500 record. However, that offense was very much feast or famine, with 70% of the tally coming in just three contests, with the other seven games leading to only fifteen runs combined. All told in 2017, Arizona have an 8-0 record when delivering tacos by scoring more than four, but are 0-6 if held to fewer than three runs.

The projection systems

• Baseball Prospectus: 37.0% (12.1% div, 24.9% wildcard)
• Fangraphs: 26.8% (5.4%, 21.5%)
• FiveThirtyEight: 39% (20%, 19%)

[Tip of the hat to shoewizard for help here] Fangraphs is the only one which I quoted in the previous report; since then, the D-backs’ chances have increased from 18.2%. As of the 30-game round-up, I’ll track how the other two have changed as well. The chart below shows how the Fangraphs odds have ebbed and flowed over time. The Dodgers are still well over 90%, but Arizona has now overtaken the slumping Giants - and, to be honest, I think the current estimate for San Francisco, of around 25%, is likely about 24.5% too high.

Prospectus says that the D-backs’ odds have increased by 11.1% over the past week. However their adjusted standings still have the Dodgers on top in second- and third-order wins. To explain those: first-order wins are based on runs scored and allowed. Second-order is based on the expected number of runs given the offense - the D-backs get dinged here for being so clutch, something generally deemed not sustainable. Third-order takes the second-order figure, and also takes into account quality of opposition. While Arizona are close to their actual record in first-order wins, they’ve overperformed by 1.5 wins in second-order, and 1.9 in third-order.

Nate Silver’s FiveThirtyEight site gives Arizona their best chance of making the post-season, and is also the only one to see us as more likely to win the division than make it as a wild-card. They also have a page giving the odds for this week’s upcoming games, and it’s good news for the D-backs, who are favored in each contest. The numbers are particularly strong (as you would probably expect) for the Padres’ series, where our odds start at 59% for the Corbin-Richard match-up, and go as high as 63% for tonight’s game between Greinke and Chacin. Last week, Arizona was favored to win three and lose four, and they flipped the script. So, here’s to a 7-0 week!

Previous 20-game records

As at the 10-game mark, I’ve analyzed the results since 1998 of all 570 teams at the 20-game point, and whether or not they made the post-season. The chart below breaks down the records, and also lists the teams occupying each band in the 2017 standings [for teams that haven’t played 20 games, I’ve used win percentage to decide their block]

If your win percentage doesn’t begin with a four or better, you can pretty much kiss your season goodbye. Just four of the 92 teams to get off to a 7-13 or worse record in the last 19 seasons saw playoff action. The lowest 20-game record to make the playoffs belongs to the 2002 Angels, who began the year by going 6-14 - but they immediately started an eight-game winning streak, which hauled them back to .500. In fact, they lost only three of their next twenty-four contests, on their way to 101 wins. So, while we can’t utterly rule out the Giants or Braves yet, they had better get their skates on, stat. Like in the next week, or they’ll have their pick of tee times in October.

Note the slight discrepancies here: 12-8 has a slightly lower chance of post-season play than 11-9, and 10-10 has historically been worse than 9-11. But the difference is within the bounds of random fluctuation. Both the 12-8 and 11-9 numbers are within the range of the numbers given by the other projection systems, so there’s a reasonable consensus that the D-backs currently have about one chance in three of making the playoffs. A good week over the rest of this homestand, perhaps going 5-2 against the woeful Padres and surprising Rockies, should go a significant way to seeing that number trending in the right direction, by the next time we check in.