Below you’ll find today’s ZiPS stretch run update. For details on just what’s going on here, please refer to my original article describing all these mathnanigans.

American League Wild Card

The Yankees have now reached the point where a win nearly clinches a playoff spot, though it doesn’t make one a mathematical certainty. With one more win, the Mariners and the Red Sox would both have to sweep their weekend series and the Yankees would have to lose out in the tiebreaker in order for New York to miss the playoffs. Similar to our probables grid, I’ve tentatively put in a short outing for Luis Severino on Sunday. The Yankees have been mum about their starter plans for that game, and as the team most likely to cement the top Wild Card spot before Sunday, they could also go total slop time so that they have as much strength as possible before next Tuesday’s play-in.

Boston and Toronto’s losses are a Very Big Deal. Losing a game they were favored to win nearly 70/30 pushed the Red Sox to the outside in a lot of simulations, while the Blue Jays lost their remaining Robbie Ray game (unless there’s a complicated tiebreak scenario).

As for Seattle’s projection, not unexpectedly, the game-by-game numbers have caused a lot of consternation. Remember, these are projections, and while the Mariners have won all these games (and those wins are part of the permanent record), a projection is going to know that they’ve greatly outperformed their runs scored/runs allowed and that they’ve scored more runs than their runs created or similar measures. Doing that is not actually predictive of continuing to do that; closer quality is the closest thing I can find related to Pythag outperformance and we’re talking a dreadful R-squared of 0.026. Nor is Seattle’s win-loss record in Chris Flexen’s starts predictive. ZiPS sees regression from Flexen, isn’t a Tyler Anderson fan, and absolutely hates Seattle against left-handed pitching.

Every year, there are calls for me to put the thumb on the scale for some team that’s defying expectations, but there’s approximately a 0% chance that I’m going to do that, even if I thought it would make the projections more accurate. The burden of proof on “This Time is Different” is quite high, when it’s been no different for pretty much every other team in baseball history. And didn’t we just do this with the 2018 Mariners? I’m personally rooting for the Mariners (and the Blue Jays), but if I can’t change the projections, there’s certainly nobody else who can!

In any case, let’s forget all that and put the thumb on the scales anyway to see what happens! The break-even point for the Mariners to catch the Red Sox in the playoff projections as of now requires a pretty big boost: I’d have to change Seattle’s expected per-game winning percentage to .587 to have them pull even with the Red Sox. The basic fact is that Boston and Toronto are playing against worse teams than the Angels, even with Shohei Ohtani shut down as a pitcher.

The four-team tiebreak scenario has become a long shot with the Yankees win. It now requires a Rays sweep, a Jays sweep, and both Boston and Seattle winning exactly two of three games. That’s down to 0.6%. There’s a better chance overall (another 9.7%) that none of the remaining four teams have been eliminated after Sunday, but that’s from the less exciting scenario of the Yankees being in the first Wild Card spot and just waiting out a three-team dance. Overall, there’s a 41.7% projected chance of bonus baseball, though it would be of the relatively prosaic two-teams-playing-one-game variety.