We’re basically a quarter of the way through the season. About 60 percent of the league will have played at least 40 games by the time you read this. This early landmark of the season has a funny way of sneaking up on us, because of the disruptions in the early-season schedule—extra off days, rainouts, and so on—and because of the distractions that keep baseball off the front page of the sports section until summer: the NFL Draft, the NBA and NHL playoffs, etc. We spend so much time (rightfully, by the way) reminding ourselves that it’s early that we eventually risk doing so even when it’s no longer so.

I’m not sure we’re there yet. I’m not sure it’s not still early. Rather than revisit this in two weeks and find I missed the crossing of the Rubicon, though, I figure it’s worth taking stock of what’s changed so far. To do so, let’s examine the 10 teams whose Playoff Odds have moved 12 percentage points or more since the season began. This is an imperfect way of deciding how much has changed, of course. It embraces both PECOTA’s initial estimation of each team’s true talent level, and the system’s rate of change—the way it incorporates new information without giving up the value added by maintaining a long memory and healthy skepticism about relatively small samples. Still, it’s something, so let’s test out the relationship between our intuitions and PECOTA’s projections.

Playoff Odds Risers

White Sox: 37.5 percent to 73.3 percent

PECOTA had the Indians as the preseason favorites in the AL Central, and it wasn’t all that close. The system forecasted 89 wins for Cleveland, and 82.8 for the White Sox. With Chicago out to a three-and-a-half-game lead, though, it’s allowed the Sox to nose out in front of the Tribe. That doesn’t mean it’s totally changed its mind about the true talent level of the teams: it’s increased the White Sox’s projected rest-of-season winning percentage only from .511 to .518, and lowered Cleveland’s only from .550 to .541. That convergence (which seems fair, to me), coupled with Chicago’s cushion, has tilted the scales in the division.

Interestingly, the big thing the White Sox have done to get this far is to play much better defense than most people thought they would. They have the fifth-highest Park-Adjusted Defensive Efficiency in the majors, which helps cover the abundant holes in a roster that has the 18th-best TAv, seventh-best DRA, and third-worst BRR (Baserunning Runs) in baseball. They’re out over their skis, in a sense, but their success so far hasn’t been a total fluke. They have the third-highest third-order winning percentage in the AL. If they didn’t, it’s likely PECOTA wouldn’t be so ready to take them seriously.

All of that only explains about half the change in their Playoff Odds, though. Indeed, most of the teams on this list haven’t really turned PECOTA upside-down. A significant share of every change comes from the way other teams have performed. In this case, the predictable poor performance of the division’s three also-rans has cemented Chicago’s spot as the Indians’ top rivals for the division title. (The Twins have been even worse than was predictable, frankly, but PECOTA already didn’t think they would be good. We’ll get to them later.) The uncertain terrain of the AL West has also helped, by boosting the Sox’s chances of sneaking in as a Wild Card team.

Red Sox: 44.3 percent to 79.3 percent

Strong starts from some hitters about whom PECOTA had certain reservations (Jackie Bradley, Hanley Ramirez) have helped assuage the system’s doubts about a team it used to habitually overrate. In fact, the Red Sox have one of the top two or three offenses in baseball, if the first quarter of the season is to be trusted, which explains just about all of this improvement. Sure, it helps that the Rays and Jays are both hanging in the race by the skin of their teeth, scuffling and below .500, and it helps that PECOTA doesn’t particularly believe in what the Orioles have done so far. (Well, it kind of does, but no team that entered the season with single-digit Playoff Odds is going to persuade the computer to make them favorites by mid-May.) For the most part, though, what this says is that PECOTA sees reasons to believe even more in the Red Sox’s strong offense than it did before the season, and that the underperformance of some of the team’s key pitchers is a concern more than outweighed by all the things that have broken their way.

Mariners: 44.5 percent to 73.3 percent

PECOTA still believes the Astros will be better than the Mariners for the rest of the season (by a minute margin, .527 to .525 in projected winning percentage, but an edge is an edge). Seattle has been a little bit better than that so far, though, and the Astros have been sufficiently worse as to make this race look like a cakewalk on the Playoff Odds page.

Here’s where it’s important to be careful when reading those numbers. They rest on the assumption that the Rangers kind of suck. Prior to the season, the system saw Texas as a .491 true-talent team. Seven weeks later, despite their 22-18 record, the Rangers have a .450 third-order winning percentage, and PECOTA buys more into the latter than the former. Texas’s updated rest-of-season winning percentage projection is .482. Because of that, despite the fact that the Rangers are nipping at the Mariners’ heels in the standings, the Playoff Odds say Seattle is sitting pretty. I wouldn’t discount the cautionary note PECOTA is sounding about the Rangers, but I would say that a safer estimate of the Mariners’ Odds might be in the low 60s.

Orioles: 7.8 percent to 32.9 percent

Yes, Mark Trumbo and Manny Machado are off to big starts, and yes, PECOTA has adjusted its expectation for each up slightly (from a .271 Tav to a .273 for Trumbo; from .278 to .283 for Machado). Looking at things through a wide-angle lens, though, the computer isn’t impressed by Baltimore. Their rest-of-season projected winning percentage is .478. They’ve gone from a very long shot to a legitimate contender, which is significant progress. From here, they have an honest chance to make a run at the postseason. That they aren’t a favorite is affirmation that, yes, some things are starting to carry real meaning, but it’s still early.

Cubs: 83.9 percent to 98.1 percent

The Cubs’ start has fried everyone’s circuitry—even PECOTA’s. Their dizzying run differential, second-order and third-order winning percentages have effected a comparatively huge jump from a preseason projected winning percentage of .560 to an updated rest-of-season projection of .570. Blend that higher expected performance with a 27-10 cannon shot of a start, and you have a heavy favorite who have already made themselves a mortal lock to don T-shirts and hats with the tags still on in October. The loss of Kyle Schwarber actually did dampen the system’s enthusiasm some. That check mark in the ‘Con’ column just hasn’t been any match for the mounting ‘Pros’.

Playoff Odds Fallers

Astros: 56.7 percent to 26.1 percent

We spend so much time talking about the fact that 87 or 88 wins can often get a team into the playoffs, these days, that we might not be talking enough about how good a team that wins 87 or 88 games really is. There’s a notion out there that any team capable of going .500 is also capable, in a slightly more remote way, of going 87-75 and sneaking into the second week of October. That’s not really accurate. Those teams are capable of doing that, but the remoteness of the chance that they will is often underestimated. It’s harder to go 87-75 than we think, is what I’m saying. That’s why, though few hot starts guarantee a playoff spot, a very cold start can much more effectively foreclose the possibility of one. Bad teams can go 24-16 sometimes. It’s very, very rare for a playoff-caliber team to go 16-24.

Enter the Astros. PECOTA thought they would be good before the season, and it still thinks they’re good now. It projects a .527 winning percentage for their remaining games, identical to the figure it projected before their season began. It sees no change in their true talent, at least in aggregate, and yet, their playoff hopes have been halved. That’s what a bad start does. That’s how little margin for error there still is, if you want to reach the playoffs.

Yankees: 34.3 percent to 8.4 percent

The Yankees are that team to which I passingly referred in discussing the Astros: they came into this season with a PECOTA-projected winning percentage of .506, and so some people nodded and said, “Okay, they have a chance, this is a fringe contender.” Maybe they were, or could have been. Maybe any true-talent .506 team really has a little better than a one-in-three chance to win 87 games and take down the Wild Card. But now, PECOTA sees the Yankees more clearly. It has their projected winning percentage down to .492. It realizes the Orioles are better than it thought, and it still likes the Blue jays and the Red Sox and the Rays pretty well, and anyway, Boston and Baltimore are off to those great starts. The Yankees are finished, is the hint here.

Blue Jays: 45.2 percent to 26.8 percent

Most of the difference here is in the reduced chances that the Jays win the AL East. Maybe that’s sounding redundant to you, by now. Don’t worry, the Rays aren’t on this list, this is the last AL East team we have to account for. It’s really a pretty interesting case. Here’s a situation where PECOTA foresaw a four-way race and very little in the way of separation between the teams. It figured they’d all be good, but none would be able to distance themselves from the pack. Forty games into the season, two teams have violated that implicit expectation, and one of them is the one team the system thought it could almost count out. Looking closely at the direction and magnitude of change for each team is a good way to see just how our system responds to that kind of informational shakeup. To me, it seems pretty responsive. I wouldn’t be likely to change my forecasted order of finish or the probabilities I’d assign to each team’s chances of making the playoffs this much by now. The whole point here, though, is that we humans might not be changing our minds quickly enough (or that we might be changing them too quickly, and too often, and ending up riding whichever part of a wave a surfer isn’t supposed to ride, lest she wipe out). The Jays are who PECOTA thought they were. With the Red Sox threatening to run off with the division, though, and the upstart Orioles staking their claim as true contenders, there’s no letting Toronto off the hook.

Twins: 17.3 percent to 0.7 percent

This is the kind of start that gets people fired, in places where people ever get fired. This is the nightmare. This is, without regard to the strong start from the White Sox, the kind of start from which it is impossible to recover. The worst start ever by a playoff team, by the 1914 Miracle Boston Braves, was 12-26. It was so long ago games could be declared ties, and even they weren’t as bad as the Twins have been. The only reason the Twins haven’t fallen more than anyone else is that PECOTA never believed in them much anyway.

Diamondbacks: 19.9 percent to 7.9 percent

Believe it or not, since the season began, PECOTA has raised its esteem of the Diamondbacks. They were projected for a .488 winning percentage on Opening Day, and the system now sees them winning at a .489 clip the rest of the year. Okay, the difference is infinitesimal, but the point stands. That’s a surprising thing, isn’t it? Well, not really. The Diamondbacks have started 19-23. They’ve played a couple more games than most of their competitors, so they’re providing more new information and they have less time to flip the script, and on top of all that, they’re below .500. When you’re already chasing two teams in the Playoff Odds Report on Opening Day, when PECOTA doesn’t like you as much as it likes (not one, but) two of your divisional rivals, you don’t get to go 19-23. Again, the margin for error just isn’t there.

***

So, what have we learned? Maybe nothing. It’s okay if this just provides a quick-and-dirty idea of which teams have most changed their identity (with respect to playoff contention) since the season began. At best, though, I hope it’s helped you (it’s helped me, at least) to get a slightly firmer handle on where the season’s early inflection points are, how important (or unimportant, or important in some cases but not in others) the first 40 games really are. I’m all for finding objective expressions of the subjective feelings we get about teams at about this time of year. I like this exercise for that reason.