One of my favorite tools we have here is our Playoff Odds page. I used to make frequent use of Cool Standings, and I keep track of hockey playoff odds at Sports Club Stats. I like looking at the playoff odds because they give the clearest sense of where things stand, and in theory, the whole point is getting to October, so why not monitor how likely that is in real time? Of course, we’re not just in it to see the playoffs — if that were the case, most baseball fans would be pissed off all the time, if they’d be fans at all — but getting to the postseason is at the core of most of what we talk about. Why do we care about player analysis? Good players make teams better. Better teams are more likely to go to the playoffs and win the World Series. And so forth.

Eventually, on our Playoff Odds page, you’ll be able to click through and see how the odds have changed over time. That hasn’t rolled out yet, though, nor are people probably even thinking about it in the first week of April. The season is so new we’re all still trying to find our baseball-fan footing, and it feels like the whole thing is in front of us. Most of it is, to be sure, but what’s already happened counts. And it turns out, what’s already happened for a few teams is pretty significant.

This graph is going to say pretty much everything:

If you want to know where teams stand today, go to the Playoff Odds page. This graph shows how much the odds have changed, in percentage points, from just the start of the year. Note that this is through Thursday, and doesn’t consider Friday games already complete. Note also that I’m pretty sure the Dodgers/Diamondbacks games in Sydney are excepted, so, for them, this is showing the Dodgers’ change since being 2-0, and the Diamondbacks’ change since being 0-2. That’s why the Dodgers have lost a tiny bit of ground, and there’s also the Clayton Kershaw injury factor. Also, these come with error bars, because the odds aren’t based on enough simulations to completely eliminate the noise.

But at either end, there are some really interesting data points. The Mariners are already up eight percentage points, despite having lost in extras Thursday night. The Giants are right there with them, having taken three of four from a division rival. It’s never too early for higher-leverage games, and not only does beating a rival give you wins and give them losses — it reduces the number of opportunities for those games to be taken back. Arizona has lost ground to San Francisco, and the two now have four fewer scheduled head-to-head games to play.

Over on the right, we could talk about Colorado or Arizona, but really, this should be about the Angels. In three games — three games! — the Angels’ playoff odds have dropped by ten percentage points. They were swept at home by a rival, and now the Angels have the worst playoff odds of the AL West foursome. They have lower odds than the Indians, and lower odds than the Braves. A few days ago, it was entirely reasonable to think of the Angels as the most likely team to win the division. This quickly, they’ve fallen behind, and whatever you thought of the Angels before, now you have to include in that projection an 0-3 start.

The best way to think of what’s happened to the Angels? On average, if you allow a leadoff home run in the top of the first, you lose about ten percentage points of win expectancy. There’s still a lot of game to go — pretty much all the game to go — and people are stunned more than anything else, but from that point forward, you have to outscore the opponent by two instead of one. That run goes on the scoreboard immediately and it doesn’t come off, and just because it happened quickly doesn’t mean it matters less. The winning process can start out of the gate, and the same is true of the opposite.

After a slow start a year ago, the Angels were a better-than-average baseball team. After a slow start the year before, the Angels were one of the best baseball teams in the majors. In neither year did the Angels make the playoffs, so they understand better than most the importance of not doing what they’ve already started doing. The good news is they get the Astros on Friday, but then the Astros are much improved and our playoff odds account for schedule strength.

Hit a leadoff home run and you know you still have a full game to play. Allow a leadoff home run and you know the same thing. But a leadoff home run does change the dynamic, and sometimes games end 1-0. Just because you might not be ready for baseball yet doesn’t mean baseball hasn’t already started happening, and there’ve already been a few plot-changing twists.