The Arizona Diamondbacks' offseason is defined as much by calendars and deadlines as by trades and free-agent chatter. A clutch of leaguewide events and club-specific cutoffs between November and February will dictate who the team protects, who it pays and how it replenishes the roster heading into the 2026 season.

The industry’s first focal point arrives Dec. 8-11 with the Winter Meetings in Orlando, Fla., where the MLB Draft Lottery on Dec. 9 and the Rule 5 Draft on Dec. 10 create windows for roster turnover and strategic acquisitions. The latter especially pressures teams to finalize their 40-man rosters in mid-November to shield prospects from selection. Teams must add eligible players by 4 p.m. MST on Nov. 18 if they want to protect them from the Rule 5 Draft.

Contract mechanics and arbitration timing will also compress front-office calendars. Clubs and eligible players will exchange arbitration figures on Jan. 8, 2026, with tender decisions coming earlier: by 6 p.m. MST on the Friday before Thanksgiving — Nov. 21 — teams must tender contracts to unsigned players, including those eligible for arbitration. Non-tendered players immediately become free agents, a procedural deadline that often triggers market movement and recalibrates payroll projections.

One headline financial note for Arizona: Gallen is the only Diamondbacks player slated to receive a qualifying offer, a one-year, $22.025 million deal for 2026. The deadline to extend that qualifying offer is set at 3 p.m. MST on the fifth day after the conclusion of the World Series, and players have until 2 p.m. MST on Nov. 18 to accept. These windows create short, high-stakes decision cycles for both player and club, forcing rapid evaluations of value versus long-term strategy.

International talent acquisition frames the longer-term roster blueprint. The 2025 international signing period ends Dec. 15, while the next window opens Jan. 15, 2026. Those bookends concentrate scouting, budget allocation and negotiations and underscore a growing industry emphasis on global player development as teams attempt to hedge against domestic free-agent inflation and talent scarcity.

On-field preparations follow the administrative flurry. Pitchers and catchers report Feb. 11, 2026, with the full squad convening Feb. 16. Those dates anchor spring training timelines and provide the first tangible assessments of how offseason decisions translate to depth, role clarity and competition for roster spots.

Collectively, these deadlines illuminate broader trends in baseball: compressed decision-making, the premium on prospect protection, and the balancing act between short-term competitiveness and long-term financial flexibility. For fans, the winter calendar is a roadmap to expectations; for the organization, it is an operational gauntlet that will define payroll, shape the farm system and influence Arizona’s competitive window. As the Diamondbacks navigate this sequence of cutoffs and meetings, each date will ripple through scouting priorities, contract strategy and the clubhouse composition fans will see in February.