We can write about the prospects who can’t locate glove-side, we can write about the fantasy implications of a fourth-outfielder logjam, we can write about the strengths and weaknesses of each player traded and we can give our best assessment of each team’s competitive windows. But what you really want to know is this:

Are the Brewers (or the A’s, or the Orioles, or name a team) any more likely to make the playoffs today than they were before they made the TA-worthy trade? Any by how much?

So here we’ve run the playoff odds report before and after every major trade at this deadline, starting with Felix Doubront to the Cubs. (That one didn’t change much.) We’ve reset the depth charts for each team, then let PECOTA have a go at the rest of the season. We’ll focus on how each move affected specifically the team that made it, though of course any added percentage points gained (or lost) have to come from (or go) somewhere, so the other teams’ odds are changing along the way. Here are the major moves of the July 31st trade deadline, as told through a series of changing playoff odds:

(Note: Playoff odds are chances of making any postseason appearance. Adjusted playoff odds are the chances of making a division series, either by winning the division or winning the wild card game.)

Cardinals trade for Justin Masterson
Cardinals before: 53.4 percent to make the playoffs; 42.8 percent adjusted.
Cardinals after: 53.4 percent to make the playoffs; 43.7 percent adjusted.

A's acquire Jon Lester and Jonny Gomes for Yoenis Cespedes
A’s before: 63.9 percent to win the division; 82.6 percent adjusted
A’s after: 66.1 percent to win the division; 83.9 percent adjusted

Joe Kelly and Allen Craig traded by Cardinals to Red Sox for John Lackey
Cardinals before: 54.1 percent playoffs; 43.6 percent adjusted
Cardinals after: 52.9 percent playoffs; 42.4 percent adjusted

Gerardo Parra traded by Diamondbacks to Brewers
Brewers before: 66.4 percent playoffs; 52.3 percent adjusted
Brewers after: 65.9 percent playoffs; 51.5 percent adjusted

Nationals acquire Asdrubal Cabrera
Nationals before: 75.0 percent division; 81.3 percent division
Nationals after: 76.7 percent division; 83.3 percent division

Mariners add Austin Jackson for Nick Franklin
Mariners before: 18.7 percent playoffs; 8.9 percent playoffs
Mariners after: 19.3 percent playoffs; 9.3 percent playoffs

Tigers add David Price for Drew Smyly, Austin Jackson
Tigers before: 87.3 percent division, 89.1 percent adjusted
Tigers after: 86.7 percent division, 88.2 percent adjusted

Rays trade David Price for Drew Smyly, Nick Franklin
Rays before: 11.3 percent playoffs, 7.9 percent adjusted
Rays after: 10.4 percent playoffs, 7.3 percent adjusted

Yankees trade Kelly Johnson; acquire Stephen Drew and Martin Prado
Yankees before: 16.2 percent playoffs, 11.4 percent adjusted
Yankees after: 17.5 percent playoffs, 12.3 percent adjusted

Orioles trade for Andrew Miller
Orioles before: 76.7 percent playoffs, 64.8 percent adjusted
Orioles after: 77.0 percent playoffs, 65.2 percent adjusted

And, for the grand finale, the day’s starting and ending World Series odds for all 30 teams:

Team Starting odds Finishing odds Change
ANA 14.1 13.8 -0.3
ARI 0 0 0
ATL 2.6 2.2 -0.4
BAL 4.5 4.7 0.2
BOS 0 0 0
CHA 0.1 0.1 0
CHN 0 0 0
CIN 0.6 0.6 0
CLE 0.8 0.7 -0.1
COL 0 0 0
DET 12.1 12.6 0.5
HOU 0 0 0
KCA 0.9 0.6 -0.3
LAN 16.5 16.8 0.3
MIA 0.1 0.1 0
MIL 3.7 3.6 -0.1
MIN 0 0 0
NYA 0.7 0.9 0.2
NYN 0.1 0.1 0
OAK 14.1 15.2 1.1
PHI 0 0 0
PIT 2.8 2.8 0
SDN 0 0 0
SEA 0.9 1.1 0.2
SFN 3.7 3.8 0.1
SLN 3.5 3.5 0
TBA 0.9 0.9 0
TEX 0 0 0
TOR 5.8 4.4 -1.4
WAS 11.8 11.8 0

So how to process these. First, I’d recommend not getting too hung up on any individual projection. PECOTA hates John Lackey, for instance. You might not. It’s fine that we have disagreements, and if you want to stick with your belief that there’s no way the Cardinals got worse by trading for Lackey, I’ll stand right there with you, friend. The more important lesson to take from this is what connects all of these: The changes are incredibly small. No team went from a borderline contender to the favorite, no matter how good the player they added. If the Tigers win the World Series, or the A’s win the World Series, it will be aided by the trades made yesterday—but it’s only a small part of the vast project that each team’s front office has been building all these years.

The best you can realistically hope for is that one extra out gets put in the deck for you before the river. A couple-percent bump to make the playoffs, maybe one percent to win the World Series. It’s awfully hard to break a team with one injury, and it’s awfully hard to make it something it’s not with one trade.

Huge thanks to Rob McQuown for helping put this together.

Thank you for reading

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pretty remarkable to see the Blue Jays WS probabilities fall by 25% for standing still.
And still have the 7th highest odds, somehow
Has to be a bug. Fell by -1.4, nobody else fell more than -0.4.

Even Tampa Bay's odds stood still (among those with non-zero odds) while trading away Price.
Not likely a bug. Division opponents Baltimore and New York both improved, even if only incrementally. Seattle gained a tiny bit of ground in the wild card race. The Blue Jays lost ground by doing nothing.
NY, Bal, and Sea all improved by +0.2. Combine that and it's less than half of what the Jays fall.

I can understand a team's odds falling by doing nothing while others improve, like KC and LAA falling -0.3. Tampa Bay faces the same division opponents, trades one of the best pitchers on the planet, and their odds stand still.

It's the magnitude, the -1.4 drop that is not credible. I'd put the odds at 95% this is a bug. 5% that it has a legit explanation.
The system thinks that the A's and Tigers are more formidable postseason contenders, which is where the Blue Jays' drop largely comes from. As a percentage change, the Blue Jays' World Series odds dropped about twice as far as their adjusted playoff odds.
(Note: This is an explanation, but it's not necessarily THE explanation and it's not necessarily that you're wrong. I'm looking into it, just in case.)
One other thing: These are based on simulations, so there will be some (usually very small) amount of fluctuation every time we run them. It looks like the Blue Jays' baseline was a little bit on the high side, that there was a statistically unlikely series of spins that skewed their baseline a bit. (For instance, their observed odds dropped when Felix Doubront got traded, while the other teams in the division improved slightly.) So part of the Blue Jays' drop might also be statistical regression.
Makes sense. Having a 4.4% chance makes sense compared to the 4.7% chance for the Orioles. I see PECOTA has the Jays as the better team, but the O's being 2.5 games ahead before last night is a pretty big deal.

The 5.8% initial chance looks to be on the high side, when compared to Baltimore.
Thanks for looking into it, Sam.
Could also have to do with remaining schedule. If the Jays have to play most of their games against the teams that improved and have already played most of their games against the teams that sold and got worse, then the impact could be larger. I don't know that this is the case (and doubt it) but it might explain part of it too.
I see the Tiger's playoff odds actually went down. Does that have more to do with them losing yesterday than with Price?
Yesterday's games are not included in this.
The chances of Detroit making the playoffs went down, but their chances of making the World Series actually went up. That demonstrates the importance during the playoffs of a team's top three starters.
I think its more a function of the other teams getting stronger. If the tigers hadn't made the deal they might have dropped even more, like the nays did for standing pat. They have a scary rotation but so do other teams now, and they don't have detroits lineup issues (ajax leaving hurts the lineup almost as much as the defense)
Love this approach, thanks for running it.

It'd be a lot more work, but how about running some other scenarios, making assumptions that disagree with PECOTA. For example, assuming Craig/Kelly would not have contributed to the Cardinals this year and that Lackey will have a 3.50 ERA going forward. Or
Taking Jackson out of Detroit's outfield leaves a pretty big hole actually.
Agreed. The drop off from Jackson to Rajai Davis is steep.
And Kris Bryant homered...