Why splitting the season series with the Diamondbacks will matter in October

The race to the 2025 playoffs may be decided by how the Mets perform against the NL West.

Since Major League Baseball expanded the playoff format in 2022, the postseason has become more accessible—with 12 teams now vying for the World Series instead of 10. But while more teams have a path in, that path is far from easy. The added wildcard spots have not only intensified regular-season drama but also reshaped the competitive landscape.

The 2024 season offered a perfect example. Down the stretch, the race for the final two National League wildcard spots turned into a three-team battle between the Mets, Braves, and Diamondbacks. With games 161 and 162 serving as virtual playoff games for the Mets and Braves, the Diamondbacks were ultimately left out—losing a tiebreaker based on the head-to-head split.

As this season unfolds, the playoff picture promises to be just as crowded. Each division winner earns an automatic bid, while the three remaining spots go to the non-division winners with the best records. Last year, the NL East secured two of those wildcard berths; this year, the NL West is shaping up to be even deeper. It’s entirely possible that the Dodgers, Padres, Giants, and Diamondbacks could claim all three wildcard slots—leaving NL East contenders like the Mets, Braves, and Phillies with a steep hill to climb.

For the Mets, the clearest path is winning the division outright, but that’s no guarantee. They currently hold a 2.5-game lead over the Phillies and a 5.5-game cushion over the Braves. But if recent history has taught Mets fans anything, it’s that no lead is safe. Just two seasons ago, a 10.5-game lead in June vanished by September, a collapse that still lingers as a cautionary tale.

While games against division rivals will naturally get the spotlight, matchups with NL West opponents could be just as decisive. Earlier this week, manager Carlos Mendoza faced questions for not using Edwin Díaz in a close game against the Cardinals—a game the Mets nearly rallied to win. The takeaway is clear: wins in May count the same as wins in September, and with limited opportunities left against the NL West, each one could prove crucial.

If teams finish the season tied for the final playoff spot, MLB uses a tiebreaker formula rather than a one-game playoff. Here’s how it works:

1. Head-to-Head Record: The first tiebreaker is the season series between the teams. For example, if two teams tie and one won more head-to-head games, that team advances.

2. Intradivision Record: If the head-to-head record is tied, the next tiebreaker is the teams’ records within their own division.

There are additional steps if both of these are tied, but in the case of the Mets and Diamondbacks—who split their six games this year—the next deciding factor would be intradivision record. Given the strength of the NL West, the Diamondbacks are likely to finish with a weaker division record, giving the Mets the edge in a potential tie.

In a crowded field where every margin matters, the Mets must stay sharp—not just against their division, but across the league, and especially against the NL West. October might feel far off, but the race has already begun.