MLB 15: The Show is a single-player and multiplayer sports simulation game. The game places players into the world of Major League Baseball, offering the chance to control professional teams, guide a single athlete through a career, or manage a franchise across multiple seasons. The player can take part in individual games or long-term campaigns where success is measured by performance on the field, statistical growth, and management decisions.

Core gameplay involves batting, pitching, and fielding, all designed to mirror the strategies of real baseball. Hitting uses timing-based systems where swing accuracy, player attributes, and pitch recognition determine outcomes. Pitching features a variety of mechanics, from meter-based controls to more advanced timing models, with stamina and confidence influencing results. Fielding requires positioning, reaction speed, and accuracy when throwing, while base running demands precise timing for steals, leads, and slides.

Progression is central to the Road to the Show mode, where the player creates a custom athlete and develops their career from the minor leagues to the majors. Performance in games earns training points that improve attributes such as contact, power, or fielding ability. Success can lead to roster promotions, contract negotiations, and eventual stardom, while poor performance may stall advancement. Franchise mode instead focuses on management, allowing players to trade athletes, draft rookies, and balance budgets across multiple seasons.

Additional systems include online multiplayer where players compete head-to-head, exhibition matches for quick play, and season modes that simulate real MLB schedules. Authentic commentary, stadium recreations, and licensed rosters aim to replicate the league atmosphere. Collectible baseball cards are integrated into Diamond Dynasty mode, letting players assemble custom teams from past and present athletes to compete in both offline and online matches.

Save import functionality allows progress from MLB 14: The Show to carry over into this installment, preserving player data, franchises, and career advancements.