The format has changed — so should the playbook

The pre-tournament arms race for squad depth is the wrong conversation. The 2026 tournament rewards tactical fluidity and smart rotation far more than the size of a roster, and the evidence is already sitting in Spain's domestic cup competition.

Coach after coach heading into the summer will cite squad depth as their armour — a 26-man roster packed with quality across every position. That instinct made sense for the 32-team format of 2022. It is the wrong answer for what awaits in North America.

Copa del Rey: the format mirror nobody is talking about

The Copa del Rey's 2025-26 edition has functioned as an accidental laboratory for exactly the kind of tournament architecture the 2026 tournament will demand. The competition's high-frequency match schedule, with clubs rotating across multiple rounds in tight windows, has separated two distinct approaches: teams deploying 18-to-20 player rotations built around positional fluidity, and those relying on static 23-to-25 man selections with defined, rigid roles.

The data is unambiguous. Copa del Rey sides using the leaner, fluid rotation model have outperformed their larger-squad counterparts across the competition. More tellingly, positional fluidity — the ability to shift players across multiple roles within the same tactical shape — correlates directly with tournament longevity in the Copa format. Teams built for adaptability survive the schedule. Teams built for depth alone do not.

Why 64 group-stage matches changes everything

The 2026 tournament's group stage will produce 64 matches, up from 48 in 2022. That is not a cosmetic change — it is a structural one. With 48 nations competing, fixture congestion across the group phase creates a compounding physical and tactical load that no squad manages through numbers alone. The 2022 format rewarded established depth precisely because the path from group stage to final involved a manageable cadence. The expanded format in 2026 removes that comfort.

What the Copa del Rey model demonstrates is that high-frequency match environments expose tactical rigidity faster than they exhaust physical resources. A manager who can shift between a 4-3-3 and a 3-4-3 using the same core 18 players holds a structural advantage over one who needs specific personnel to execute a specific system. When those specific personnel are unavailable — through fatigue, suspension, or injury accumulated across a denser schedule — the rigid squad fractures. The fluid squad adapts.

Spain's own squad planning for the 2026 tournament reflects this logic. La Roja's recent squads under Luis de la Fuente have trended toward players capable of operating across multiple positions rather than single-function specialists, a philosophy that maps directly onto what Copa del Rey data is now quantifying.

The counter-argument deserves a direct answer

The strongest objection to this analysis is real: World Cup knockout matches carry a pressure and physicality that no domestic cup competition can replicate. When Spain face Brazil or Argentina face England in the last 16, the physical intensity rises sharply, and squad depth becomes the difference between a fresh set of legs in the 70th minute and a fatigued one. Depth rankings still matter, and we are not arguing otherwise.

But this objection conflates two separate questions. Depth matters in knockout rounds — agreed. The argument here is about which preparation philosophy and which in-tournament management strategy survives the journey to those knockout rounds. A team that enters the round of 16 tactically exhausted because their rigid system was exposed twice in the group phase never gets to test its depth. Copa del Rey evidence shows that the teams reaching late rounds in high-density formats are the ones who arrived there through flexibility, not numbers. Depth is an asset. Flexibility is the strategy that lets you spend it.

What smart national teams should do right now

The implications are concrete. First, national team managers should be auditing squads not by positional headcount but by tactical coverage — how many distinct systems can this group of 18 execute without personnel change? Second, selection calls that have historically favoured the reliable specialist over the positionally versatile squad player should be reversed. Third, in-tournament rotation plans should be built before a ball is kicked, not improvised under pressure after a first-group-game injury.

Our call

We expect the teams that reach the 2026 tournament's quarterfinals to be tactically unrecognisable from how they opened their group campaigns — not because they abandoned their identity, but because their identity was flexibility from the start. The Copa del Rey has already shown us the blueprint. The teams that read it correctly will not be the ones with the biggest squads. They will be the ones whose smallest effective unit is the most dangerous.

The 2026 tournament does not reward the army with the most soldiers. It rewards the one with the most adaptable generals.

This article was researched and drafted with AI assistance and reviewed by our editorial team.