Welcome to September, everybody. It's been a long and winding summer of baseball so far, but the drama just getting started: Nearly every division race (sorry, AL Central) is up for grabs as we hit the final month of the regular season, and playoff positioning seemingly changes by the day. A 162-game marathon has turned into a four-week sprint to October, one where every game is critical.
Some games, however, are a bit more critical than others. After all, the best way to make up ground or hold off your rival is by beating them head-to-head, and the baseball gods are giving us a ton of juicy series with postseason implications in September. Here are the 10 biggest worth keeping an eye on across both leagues.
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Toronto Blue Jays at New York Yankees (Sept. 5-7)
New York Yankees fans have to be feeling an awful lot like Charlie Brown running to kick the football at this point. Once again, their team has picked its season up off the mat, winning seven of its last eight games to pull back within 2.5 games of the Blue Jays in the AL East. Of course, six of those seven wins came against the Washington Nationals and Chicago White Sox, which is part of the problem: As good as New York can look against subpar competition, they've made a habit of shooting themselves in the foot against their fiercest rivals.
They'll have one last chance to flip the script over the next couple of weeks, starting with three games at home against Toronto beginning on Friday. Take two of three, and suddenly their division hopes are very much alive. Fall flat again, and you can pretty much kiss this season goodbye.
New York Mets at Cincinnati Reds (Sept. 5-7)
The Mets might be the single most exasperating team in baseball right now, capable of beating the best in the league ... and then turning around and losing five of seven to the Nationals and Miami Marlins. That inconsistency has left them clinging to the final NL Wild Card spot, just two games ahead of Cincinnati to start the week.
When they're on, New York looks like a legit World Series contender. But a beleaguered pitching staff and a maddeningly inconsistent offense have let them down at inopportune times; if it happens again in Cincy this weekend, the season could start spiraling out of control.
New York Mets at Philadelphia Phillies (Sept. 8-11)
The Mets will immediately follow that crucial series with another one, heading to Citizens Bank Park for four games against the division-leading Phillies. New York currently sits six games back in the NL East, and this is the last time the two teams will meet in the regular season; the Mets need to at least take three of four to give themselves a fighting chance. Then again, Carlos Mendoza's team has owned Philly since last October, so there's a very good chance that a division race which seemed all but sewn up a couple weeks ago suddenly becomes very interesting down the stretch.
New York Yankees at Boston Red Sox (Sept. 12-14)
We mentioned that this would be a make-or-break couple of weeks for the Yankees, and it's all too fitting that it concludes at Fenway Park — a place that's been a house of horrors for New York in recent years, dating back to the 2021 Wild Card Game. These two teams are essentially tied atop the AL Wild Card standings right now, and because Boston has already sewn up the season series (and the head-to-head tiebreaker), the Yankees need to leave their weekend in Boston with their noses in front if they want to avoid another trip to Fenway in October. By the end of Sunday, we'll know for sure whether New York is serious about contending this year — and whether the Red Sox might be primed for a World Series run.
Philadelphia Phillies at Los Angeles Dodgers (Sept. 15-17)
While the Phils are heavy favorites to win the NL East, that's not the only thing on the line for Rob Thomson's team in September. There's also a first-round bye on the line: Philly right now holds the No. 2 overall seed — and a direct path to the NLDS — by just 1.5 games over the Los Angeles Dodgers.
The Phillies took two of three from L.A. in Philadelphia earlier this year, meaning that they currently hold the tiebreaker in the standings. Another series win would put them well on their way toward a top-two seed and home-field advantage in the Division Series. The loser, meanwhile, would suddenly be staring down the prospect of a best-of-three Wild Card showdown in which anything can happen.
Seattle Mariners at Kansas City Royals (Sept. 16-18)
Right now, it feels like we more or less already know which 12 teams will be heading to the postseason; it's just a matter of what the order will be, and what the playoff matchups will look like. But there's still some suspense regarding the final Wild Card spot in both leagues, and this series in mid-September could wind up becoming appointment viewing.
The Mariners had their sights set on taking the AL West after going big at the trade deadline. Unfortunately, the offense hasn't quite taken off with Josh Naylor and Eugenio Suarez in tow, and they still find themselves three games back of the Houston Astros entering play on Tuesday. And that's not all Seattle has to worry about: All of a sudden, both the Texas Rangers and Kansas City Royals are breathing down their necks, only two back in the loss column. The Rangers have a brutal upcoming schedule and injuries to Nathan Eovaldi and Corey Seager; the Royals, though, might be poised to make a run, especially if they can win this series at home.
San Diego Padres at New York Mets (Sept. 16-18)
Speaking of the NL Wild Card chase! In addition to holding off the Reds, the Mets are also trying to catch the Padres, whom they currently trail by two games entering Tuesday. San Diego swept New York back in July, meaning the Mets would have to return the favor at Citi Field in order to flip the head-to-head tiebreaker. And there's much more than just seeding on the line here, as whoever finishes with the No. 5 seed will likely avoid the Dodgers in the Wild Card Round.
Seattle Mariners at Houston Astros (Sept. 19-21)
If the Mariners want to end Houston's reign atop the AL West, they're going to have to capitalize on the final head-to-head meeting between the two. The season series is currently tied 5-5, meaning that the winner of this series will not only gain ground in the standings but will also secure the tiebreaker should it become necessary. It's hard to imagine the loser of this series finding a way to win the division, and no one wants to wind up going on the road for a Wild Card series.
Boston Red Sox at Toronto Blue Jays (Sept. 23-25)
Two weeks after taking on the Yankees, Toronto will welcome their other chief competition for the AL East. The Jays have already cinched the season series with Boston, but it might not matter if they don't take care of business in Rogers Centre during the final week of the regular season. Win, and they could well clinch a first-round bye. Lose, and suddenly they could fall as far as the No. 5 seed and a road trip in the Wild Card Round. That's how tight the margins are right now, and for as good as the vibes have been in Toronto this summer, they've still got their work cut out for them.
New York Mets at Chicago Cubs (Sept. 23-25)
These two teams won't be competing against each other in the standings per se; Chicago currently holds a five-game lead over the Mets in the Wild Card chase. But this figures to be a very high-stakes series anyway, with the Cubs trying to catch the Milwaukee Brewers in the NL Central (and stay clear of the rest of the Wild Card pack) while the Mets could either be in a division race of their own or just trying to hold on to a playoff spot at all. Oh, and it's two marquee franchises battling it out at Wrigley Field, with both teams facing big free agency questions if things go pear-shaped in the season's final week. Good luck.