50 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

Remember when we were worried? It doesn’t seem all that long ago, when we were bemoaning the Diamondbacks failure to win a series in May. As late as the last time I wrote, on May 15, that was true. and with the loss of A.J. Pollock, we seemed to be on perilously thin ice. But Arizona has won 10 of its last 11, and wakes up this morning with the third-best record in all of baseball. The D-backs have scored 56 runs in this stretch, but it has been the pitching which has really got it done, holding the opposition to half that much, only allowing 28 runs. They’ve given up two runs or fewer in five of the last eight contests. That’ll do your win expectation good.

The projection systems

• Baseball Prospectus: 69.2% (14.7% div, 54.6% wildcard)
• Fangraphs: 63.5% (7.9%, 55.6%)
• FiveThirtyEight: 63% (20%, 43%)
• NumberFire: 73.2% (23.8, 49.4%)

We’ve added a new projection system to the summary this week, taken off NumberFire.com. Obviously, the trend across all the systems this week was up, up, up. The increase was dramatic between 25% (FiveThirtyEight) and 32% (Prospectus), as the D-backs didn’t so much climb Mt. 50%, as use it as a ramp to go soaring above and beyond it. The systems still significantly lean towards a wild-card spot, with the Dodgers remaining heavy favorites. But a scenario where three NL West teams make the playoffs is currently likely. The D-backs, Rockies and Dodgers all have Fangraph odds, for example, in excess of 60%; across the rest of the National League, only the Cubs and Nationals are above 40%

Here’s the chart from there, showing the season’s progress. It has been a startling ascent by the D-backs, increasing their playoff shot by about two-thirds in just 10 games, and pulling into a virtual tie with the Rockies. They now predict the team to win 87 games and get a wild-card spot - the former, at least, is also what the Diamondbacks would do, simply by playing .500 ball the rest of the way. Anyone else feel like, currently, that would be a disappointment?

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 30-20 level.

The bar continues to creep up. Now, if you have a losing record, less than one-third of the way through the season, history already tells us that your chances of making the playoffs is not much more than 10% (18 of 162 in the 30-team era). You can hang on to a sliver of hope if you like - the biggest, latest surge was by the 2005 Astros, who were only 18-32 at this point. But only four of the 121 teams to be 21-29 or worse reached the post-season.

At the top end of the chart, there’s a weird little valley. As you’d expect, playoffs odds, generally trend up, the more wins you get. But the 32-18 mark appears to be the Devil’s Triangle of post-season form. Of the 10 teams to have been there, only a trio (most recently the 2014 Giants) played on into October. The other seven - which include the 2000 Diamondbacks - faded away into the pack. You know who has a record of 32-18 right now? Well, if you’ve read the chart, you should do, but I’ll tell you anyway: the Colorado Rockies. We’ll see what happens.

Anyway, that valley perhaps contributes to the massive success of the 31-19 band - which, hey, includes the Diamondbacks. Seventeen of nineteen teams at that mark went on the playoffs, while only two skipped the part. A good omen, at least. Adding up the chances from here, along with the four other projection systems, we get an average of 71.7%. I’ll take that, and Zack Greinke starting this afternoon in Milwaukee, any day of the week and twice on Sundays.