Important MLB offseason dates for Mariners fans to know

For 28 of the 30 MLB teams, the offseason is quickly heating up. Although trade negotiations and free agent talks won't fully take off until the conclusion of the World Series, teams are already assessing their rosters and financial limitations to hit the ground running once things get into full swing.

So while there may not be any Mariners baseball actively being played, there are still a few key dates for fans to know if they want to keep track of how their team will look heading into 2026.

Important offseason dates for the Seattle Mariners

Contract options and qualifying offer deadline

Five days after the conclusion of the World Series

All contract options — i.e. club options, mutual options and player options — must be exercised or rejected within five days after the World Series ends. The Mariners have three of these.

In this same time period, teams will also have to decide on whether they'll be making qualifying offers to select players headed for free agency. Not everyone is eligible to receive this based on a specific set of rules outlined by MLB, and Seattle likely has no players in line to receive one. Eugenio Suárez and Josh Naylor will both be free agents, but because they were trade deadline acquisitions, they are considered ineligible.

However, many of this year's most sought-after free agents — like Kyle Schwarber and Kyle Tucker — will be eligible. And although it's rare for a qualifying offer to be accepted over the potential of a long-term contract, it has happened in the past and it is the last obstacle that must be cleared before a player is truly up for grabs and the rest of the market can proceed.

The deadline for players to accept or reject qualifying offers is 1 p.m. PT on November 18.

Non-tender deadline

November 21st

Non-tendering player means declining to offer him a contract for the following year, effectively sending them to free agency early. This is done when a player is deemed unworthy of his impending salary or roster spot, and is often the first step towards improving a roster for next season.

The Mariners have a few candidates who could be viable options to be non-tendered. And with the front office prioritizing bringing back Josh Naylor, cutting back on the current payroll could be a necessary step to get there even if the Mariners seem ready to slightly increase their overall spending.

MLB Winter Meetings

December 8th - 11th

The nomenclature is as broad as can be, but the Winter Meetings is simply a set time for MLB executives to gather and talk shop, often leading to major trade deals and free agent signings. In addition to being a critical time for teams to gather data on who's available and what price, the MLB Draft Lottery (which won't include the Mariners, since they made the playoffs) and the Rule 5 Draft will also take place during this time.

2026 Spring Training begins

February 2026

After months of rumors, negotiations, and roster moves, the new and hopefully improved iteration of the Seattle Mariners will break camp and begin their preseason preparations. Pitchers and catchers typically report first with position players arriving shortly after. The exact dates for the Mariners' Spring Training schedule have not yet been released but should be published later this fall.